I am under the impression that you know a little about the basic rules of the game. If not, just look at this tutorial. It's great and goes over the essential rules that you need to know to play the game.
So, you have learned about Magic: The Gathering. You probably have played a bit with friends or family and are looking to test your deck-building abilities. Maybe you haven't and you want to build a simple deck to take to your local game shop to gain more experience playing the game. Or possibly you are somewhat more experienced with the game, but want some more help with building good decks. Wherever you are in your quest for glory, I guarantee that this guide will help you become a better deck-builder.
What you will need:
1. Magic: The Gathering Cards
2. If you don't have cards then you will need money, or a generous friend, to get cards
3. A creative mind
Anywhere from 15 minutes to a few days, depending on your skill level and dedication to the deck-building process.
So let's get started!
Step 1: Decide What Format You Want to Play
What type of player are you? Are you a more casual player looking for some fun in your downtime? Do you want to climb the ranks of the competitive community and be the top local, national, or even international player? What you want out of Magic will determine the format best for you. I will list some of the most popular formats that people play in. Decide which one best fits you and your needs.
Standard: This competitive format plays cards from the most recent sets. After a recent change in the format, Wizards of the Coast (the company in charge of the game), decided to make sets rotate every year. This means that every year, the older sets will not be allowed in the format while the newest set(s) will be. Standard tends to be the most dynamic and unpredictable format, because rotations tend to completely change the way it is played. However, this also means that eventually you will have to change up or build completely new decks, meaning that you have to spend more money if you want to continuously play in this format.
Modern: Another competitive format that uses cards from the Eighth Edition set and forward. Unlike Standard, Modern doesn't rotate, so any cards from the allowed sets can be used, in addition to the newest sets. This format tends to be the fastest and one the most expensive, because it uses some of the best cards in Magic history. While new sets can shake up the format slightly, this one tends to be more stagnant than Standard, with the best decks staying at the top for long periods of time.
Commander: This is the most popular casual format. What makes it unique compared to others is that you construct 100 card decks (instead of the usual 60) and you can only have one copy of each card. While not going into detail about the rules, Commander games, often played with 3 or more people, tend to be very explosive and unpredictable. Because of the multiplayer nature of the game, it is the most interactive and arguably the most fun out of all the formats. However, you won't see any tournaments in this format on the competitive level.
I will briefly list other formats, both to save space and because I lack experience in these: Vintage, Legacy, Pauper, Frontier, to name a few more.
NOTE: It is always important to be aware of the cards that are banned in each format to avoid unnecessary expense.
Picture is from https://warosu.org/tg/thread/46178757
Step 2: Decide What Type of Deck You Want to Build
Once you have figured out what format you want to play, this can be the both easiest and hardest part of building a deck.
Decide what type of deck interests you. Are you more of an aggressive player, going for the all-in type of approach? Or are you a more reactionary player who likes to control the tempo of the game until you can cast your huge creatures or planeswalkers? Maybe a mix of both? You could be the type of person that likes to bend the rules and use "Alternate Win Conditions", cards that will win you the game by themselves under the right circumstances, such as the one shown above.
Whatever your style of play is, you can create a deck that you can both win and have fun with at the same time.
Step 3: Building Your Deck: Colors
Once you have found the type of deck you want to build, the next step is to decide what Colors you want to build around. For beginning players, look at cards that interest you and base your decision around that. More experienced players will want to build a deck around an "archetype", where you play cards that work well with each other and have effects that collectively increase the power of the deck.
An example is the card shown above. It is a card with Red and Black colors. In addition it is a Vampire and has a very powerful effect that works well with the Madness mechanic and other Vampires. This card would therefore go best in an aggressive Red and Black deck with a Vampire/Madness theme.
As I will go into further detail later, you want to make sure that you don't have too many colors in your deck. Decks with 3 or more colors tend to be more inconsistent because you decrease the chances that you draw lands that produce the colors you need. Beginning players will want to stick to two or even one color decks because they tend to be easier to build and buying many different multi-colored lands can be expensive
NOTE: This is not absolute and depends on the format. Some formats like Commander encourage you to play many colors because they are slower and more casual.
Step 4: Building Your Deck: Spells
With the basic outline of the deck done, now it's time to fill it in. Choose cards that work well together and support the theme of the deck. For aggressive decks you will likely want the a sizable portion of your spells to be low mana-costed creatures and pump spells. Control decks will want a lot of removal, cards that get rid of your opponent's creatures/planeswalkers/artifacts/etc and have very powerful cards that when cast will turn the game around in the later portion of the game. Combo decks will want to play the pieces of the combo and have cards that support and/or protect the combo from being interrupted. Always remember synergy. The more your spells play off of each other, the more powerful the deck tends to be.
I will continue to use the example of the Red/Black Vampires to show you what kind of cards would fit well in that deck. Stromkirk Condemned shown above is great because it enables you to discard cards, which is fantastic in a deck that encourages you to do so. In addition it powers up all of your vampires when you do. Falkenrath Gorger is good by itself, because 2/1 creatures for 1 mana are always good in aggressive strategies, but in addition to that it gives all your Vampires Madness, so that you can cast them when you would normally discard. Fiery Temper is absolutely great in this deck. Normally it is a 3 mana burn for 3 damage, but with madness it costs only a single red mana! Stensia Masquerade not only gives your attacking creatures first-strike, a nightmare for your opponent to deal with, but when damage gets through every vampire that did combat damage to the opponent will get a +1/+1 counter.
You can have up to 4 copies of any particular spell in your deck. It is up to you to decide how many. A good rule of thumb is to put 4 copies of the most important cards in the deck and work your way down. Sometimes you might have to remove some copies of cards to make room for others.
NOTE: This doesn't apply to Commander, because you can only have 1 copy of any particular card
Step 5: Building Your Deck: Mana Curve
The mana curve is one of the least talked about, yet most important part about constructing your deck. The mana curve is simply the distribution of cards with a certain mana cost, and the curve comes from the shape of the graph, looking somewhat like a shifted Bell Curve or Normal Distribution curve. You want to be efficient with your mana since you can only play at most one land per turn. When you have found the cards you want in your deck, construct a mana curve so you can see how distributed your spells are.
Aggressive decks should have a mana curve that looks similar to the one shown above. Most of the cards in the graph have a converted mana cost of 2, and cards with mana costs of 1 and 3 are a close second. The amount of cards with mana costs of 4+ then makes a steep decline. This pairs well with the intentions of aggressive decks because they want to be able to cast many cheaper creatures/spells to beat the opponent as fast as possible.
Control decks tend to have a mana curve shifted slightly more to the right than the above graph. Their peak would lie somewhere around the 3 or even 4 mana cost range because they are more about controlling the pace of the game until they can play their most powerful, high-costed spells.
NOTE: Your mana curve does not need to be exactly like the one shown above even if you are playing aggressively, but when you create your deck, the shape of the curve should at least resemble it to some degree.
Picture is from http://www.gamasutra.com/view/feature/183623/what_magic_the_gathering_can_.php?print=1
Step 6: Building Your Deck: Lands
For decks of a single color, this is the simplest part, because they only require one type of land. However, it gets more complicated the more colors are in your deck. Decks with 2 or more colors will almost always need dual lands, lands that produce two colors, to make sure you get the multiple colors that you need.
Put as many dual-colored lands in your deck as you can where it doesn't impinge on the play of the deck. For example, you might not want to run too many dual colored lands in a two-color aggressive deck because many dual lands come into play tapped if the conditions are not right, which prevents you from going as fast as you can. Slower more control-based decks have more leeway when using dual lands because they can afford to play a little slower.
In total, the total amount of lands in any particular deck can be anywhere from 18-26 lands, depending on how fast or slow it is. A good number for the average 60 card deck is about 24 lands. Test your deck with the lands you put in and see how well it plays.
NOTE: This often depends on the format. The best dual-colored lands are in older sets, so decks in those formats will tend to want to play as many dual-lands as they can.
Picture is from http://www.mtgsalvation.com/forums/magic-fundamentals/magic-general/606212-a-sets-basic-land-art-forming-one-image
Step 7: Building Your Deck: Sideboard
So you have constructed your deck. The last thing you need before you're ready to go out there and compete is a sideboard, a group of 15 cards from which you can put in and take out cards from your deck in between games.
Think of a sideboard like an extension of your deck. Put cards into your sideboard that are better against specific kinds of decks that you see often. For example, if many people are playing artifact decks, put cards into your sideboard that get rid of or at least deal with artifacts. For those pesky creature-based aggressive decks you could put in boardwipes, cards that do damage to or destroy all creatures on the field.
The sideboard is one of the hidden arts of the game. It requires a knowledge of the current metagame, that is the kind of decks and cards that currently make up the majority of the playing field. The knowledge of sideboarding is something that will take a while to master, but once done will transform you from a good to a great player.
Picture is from http://www.manaleak.com/mtguk/2016/03/5-things-magic-players-need-to-think-about/
Step 8: Test, Test, Test!
The only way to truly gauge the power level of your deck is to use it. Play against anyone and everyone you can. Play against friends, family, and strangers at home or your local game shop. Quickly or eventually you will find certain match-ups where your deck might not do that well, but that's okay. You can never have a deck that is perfect against every deck. If you find that certain cards aren't working out, then tweak the deck. Experiment with different kinds of cards until you find a combination that works best.
Picture is from http://magic.wizards.com/en/articles/archive/latest-developments/playtesting-very-first-cards-2006-04-07
Step 9: The Journey to the Top
If you have confidence in your deck(s) and your playing ability and want to take it to the next level then maybe the Pro Tour is for you. The Pro Tour is where the best of the Magic community can get invited and compete for prize money and international prestige. If that is something that interests you, you can check out the following link to learn more.
Step 10: Final Note: Be Nice
Remember that Magic: The Gathering is a game. It's an outlet and a hobby for many people. Magic is more than just winning, it's about having fun and meeting people with similar interests. Be considerate and kind to those you play against, because it might have taken them a lot of courage just to show up. Be patient with those who may not understand every card or rule. Everyone was a beginner at some point. No one likes to play against rude people and poor sports. Be the kind of player you would want to play against.
Picture is from http://www.manaleak.com/mtguk/files/2011/07/playing-magic-the-gathering-at-happy-winning.jpg
Step 11: Conclusion
Congratulations, after following all these steps you should have built or have an idea for how to build a functioning Magic: The Gathering Deck.
Thanks for bearing with me throughout this Instructable. I hope you all have found something noteworthy to be gained from it. Feel free to comment any questions you have.
Disclaimer: Any picture that hasn't been cited already was taken from gatherer.wizards.com or magic.wizards.com and I do not own the rights to any these pictures. They were all used for educational purposes.