Step 1: It's Pretty Obvious
Watch anime! It's the most important thing about being an otaku! My recommendations for starter animes: Inuyasha Soul eater Fruits basket Black butler Ouran host club Lucky star Hetalia (These are all relatively short animes of up to 80 episodes at most to 13 episodes at least)
Step 2: Read Manga
It's optional to read manga but there are many other fun and great stories I manga that aren't animes and most of the time an anime will also have a manga version which is usually better than the anime itself.
Step 3: Find Your Favorite Anime
Your favorite anime will never be set in stone, for there will always be an anime that you like the best but then you will find another that's either just as awesome or better. However your favorite anime is the anime that you always want to watch even if you've seen it over and over again. If you just can't decide, then make a top 5 or top 10!
Step 4: Find Your Anime Crush
Again just like your favorite anime it is never set in stone who your anime crush is but that one special anime girl/ anime guy is out there! You will always hear your crush's voice in your head and you will wish for them to be real but sadly they aren't :'(
Step 5: Buy Anime Stuff
You guessed it, buy tons of anime merchandise! I recommend not buying too much stuff from one anime but get a bunch of stuff from a variety of animes! Don't buy merchandise from an anime you haven't seen even if its cute because you don't even know who or what it is. If your low on money make sure to have a little pile of money set aside for your anime needs! It is optional to buy animes on DVD because that stuff is EXPENSIVE I usually just watch anime online.
Step 6: Deck Out Your Room
Cover your room in anime pictures or posters or both! That is only one corner of my room the rest of the wall and the other 3 walls all have anime stuff on it. Make sure you actually like the way it's set up and arranged.
Step 7: Learn a Bit
Learn the basics of Japanese. I'm not saying learn the entire language but learning a little helps understand anime if your watching it in English sub. Plus it's fun to annoy your friends by talking Japanese every now an then :3
Step 8: Do a Little Cosplay
I'm not saying dress up full blown but inuyasha ears (inuyasha) or making plush dangos (clannad) is fun
Step 9: Write/read Fan Fictions
It's not mandatory lol but it is a lot of fun (especially when it's about your anime crush and you) or you can write about stuff that you wish happened in an anime
Step 10: Draw/ Have Fan Comics/ Fan Pictures
It pretty much goes along with the earlier step on fan fiction
Step 11: Anime Vs Cartoon
You must know the difference between an anime and a cartoon such as: Plot Animation Epic ness Etc
Step 12: Not Being an Annoying Prick
Please don't throw your anime love in people's face and call people "Baka" and stupid stuff like that because its not fun for anyone but yourself and its really annoying so please don't do it
Step 13: Being Proud About Your Anime Love
I know what I said on the previous step but you can still be proud of your otaku nature without throwing it in people's faces like talk to fellow otakus about anime and feel free to rant about something that pissed you off in an anime but don't go into anime with someone who doesn't watch anime. Also, it's ok to not watch anime don't hate on anime haters if they keep their opinions to themselves then you should to.