All you need to learn is some yarn and a pair of needles. In this Instructable I've used medium weight yarn and somewhat large needles, so the interlocking loops would be clearer. Most knitting is done somewhat tighter than this.
Step 1: A Little Bit of Theory
All that knitting really is, is a series of interlocking loops. Let's take a look at the front pic again. I used yellow thread in one row to make it easier to see how the loops interact. The second pic shows the same piece from the other side.
The first pic shows the knit side, and the second pic shows the purl side. A purl stitch (it's spelled with a u but pronounced just like pearl) is exactly the same as a knit stitch except it's worked from the opposite side. The smoother side that looks like interlocking V's is facing you when you are knitting, and the bumpy side that looks like interlocking U's is facing you when you purl.
To start knitting, you'll need to "cast on", or fill up a knitting needle with starter loops. Then you'll knit some number of rows until the piece is the size you want. Then you'll "cast off", or close out all the loops so the knitting doesn't come unraveled again.
There are also varieties of ways to hold the needles and yarn. In this Instructable I'm using and discussing the Continental method, which basically just means the free yarn end is held in the left hand (pic 3). This end can also be held in the right hand, which is more common in the USA but to my mind a bit less efficient.
Step 2: Casting On
Here's a video of the process:
And for those who prefer text and static images:
Start by making a slip knot, leaving a length of yarn about 3 times the finished width of your project as a tail. Put the slip knot on one needle, in your right hand if you're right-handed (I am - lefties you can try it this way or reverse it, whichever works for you). Hold the long tail in your left hand, wrapping it around your first finger as in the first picture.
Next, slip the point of the needle under the loop on your finger, so that both your finger and the needle are in the loop (pics 2 & 3). With your right hand, grab the yarn end from the ball or skein, and bring it over the finger loop, between your finger and the needle (pics 4, 5, & 6).
Holding the right-hand yarn piece down, slip the loop off your finger and over the tip of the needle (pics 7, 8, & 9). Pull gently on the left-hand yarn end to close up the loop, forcing the other yarn end (held by your right hand) to loop around the needle (pics 10 & 11).
You now should have two stitches on your needle, as the first slip knot counts as the first stitch.
Continue this way until you have enough stitches. For a learning swatch, 12 or 16 is plenty. I went crazy and ended up with 32!
Step 3: The Knit Stitch
Here's how to make a knit stitch:
Holding the yarn in your left hand as shown. Wrap the tail of the yarn through your fingers in some way that feels natural - the goal is to hold it taut but not so tight that you can't pull more out as needed. Some wrap it twice around the pinky.
Insert the right-hand needle through the first (or next) loop on the left needle (pic 1). With your left forefinger, wrap the yarn around the right needle counter-clockwise (pic 2). You can also think of this as slipping the needle behind the yarn.
Keeping the yarn around the needle, bring it back through the first loop, so that the left hand's yarn comes through too (pics 3 and 4). It's easier to do than to describe!
Finally, slip the original loop off the left needle, keeping the new loop on the right needle (pic 5). You have made one knit stitch!
Step 4: Purling
Pic 1 shows the position of the left-hand yarn, in front of the work. From this position, insert the right-hand needle from the back of the work towards you through the stitch on the left-hand needle (pics 2 and 3).
Now wrap the yarn around the needle counter-clockwise, or up over the needle and around to the left (pics 3 & 4). Catch the yarn with the tip of the right needle and pull it through the loop (pics 5, 6 & 7). It helps in this manouevre to tilt the left needle tip towards you.
Finally, slip the old loop off the left needle, keeping the one you pulled through it on the right needle (pics 8 & 9). You've completed a purl stitch (pic 10)!
Step 5: Casting Off
Video of casting off:
I unaccountably missed taking pictures of all but the very last stitch, I will try to redo them soon.
When you're ready to cast off, hold the work as if you were going to knit another row. Knit (knit is a bit easier than purl but you can cast off purl-wise too) one stitch. Slip that stitch back onto the left-hand needle. Now, knit one more stitch, but instead of sticking the right needle through just the last stitch on the left needle, stick it through two - the one you slipped onto it and the one beyond. Pull the loop through both stitches. You now have one stitch on the right needle, but you've made two knits - see how this is going?
Work the whole width in this manner. At the end, you 'll have one stitch remaining. Cut your yarn and pull the cut end through this loop to lock it, and pull tight. (Pics are of this last loop)
Check out BrianSawyer's Binding Off Instructable as well, he's got better pictures than I do here.
Step 6: More Stuff
Some useful terms:
- Garter Stitch: when you knit a row, and turn and knit again, instead of purling. This makes a crosswise ribbing that has a lot of vertical stretch. The first pic shows a few rows of garter stitch.
- Stockinette Stitch: when you knit a row, and turn and then purl a row. Most things are made this way, it's got all the knit-looking stitches one one side and all the purl-looking stitches on the other.
- Ribbing: A vertical alternation of knits and purls. Commonly found on the edges of sweaters - wrist, hem, neckline. I don't have a picture of this yet but you probably have examples around the house.
- Dropped stitch: this is actually a mistake, when you slip a stitch off the left-side needle without already having pulled another loop through it. If you notice you've done this, stop and go back to fix it as it will cause a run, or ladder - it'll unravel a row all the way down.
- Decreasing: the general case of casting off. Usually this is used when you don't want to finish off all the stitches, but just some, as when you're working a curved edge like a neckline.