How to Crochet:
First, you will need to have acquired a crochet hook and enough yarn for what you want to make. Tip, if you are planning on making more than a pot holder, its best to use a pattern of some sort, which you can get at a library, and enough yarn to satisfy your pattern. Hooks and Yarn are easily stolen from grandmothers and nursing homes, but they are also really cheap at craft stores. The reason you need to buy all your yarn up front is because the dye lots change, and the color will look off.
Hook Sizes: Hooks come in many different sizes, and they can be mildly confusing if you do not know what they size difference is for (believe it or not) well obviously, the bigger the hook, the bigger the stitch itself will be. A good starting size is anywhere between an H and a K, those aren't too big, and they aren't too small. The right size is up to you, and up to how dexterous your fingers are; if you have big clumsy hands, I'd suggest something bigger till you get the hang of it.
Anatomy of a hook: there are three parts to every hook; the actual hook, the shank (the area right before the flat spot, this is where you size your stitch and hold loops waiting for completion) and the handle.
How to hold your hook and yarn: Depending on whether or not you are right handed make a difference. Honestly, it is best to be right handed, since 'How To' books tend to have pictures suited for the right handed, but you can hold a mirror to those pictures if you are left handed, to get an idea. The easiest way to hold a hook is by holding it with your first three fingers of your right hand. I hold the flat part in between the shank and the handle with my crooked first finger, and thumb, it allows me to twist the hook around to get the best stitch.
Maintaining proper tension on the yarn, or whatever your using, is fairly important, since this, along with sizing your stitches, dictates whether or not the stitches are even. There are many ways to hold yarn, my mom weaves the yarn in between her fingers, where as I simply dictate the tension by running the yarn over my first finger and into my palm and to tighten the stitch I spread first finger and thumb. This will take practice to come up with your own way of holding everything, but your goal is to make even stitches.
You start all projects with a simple slip-knot (no, not the band) placed onto the shank. In junction with the skip-knot are what are known as chain stitches. This is the most important part of crocheting, if you cannot get this part, you cannot continue.
Chain Stitch: once you have your slip-knot, you have to build whatever your making off of a base, this is that base. To make a chain stitch, you must first hold the 'tail' of the knot with your thumb and second finger of your 'left' hand, while wraping the yarn from back to front on the hook, only once . Once you have the yarn wrapped around the hook, you can pull it slowly through the hole by twisting the tip if the hook toward the base of the hole; doing this will help you pull it through easier. One you have the yarn through the hole, this will create your first stitch, you have to size it on the shank, you do this by pulling swiftly (not too hard) with your forefinger (in my case, which is mildly recommended). Don't pull too hard, or you'll make it too small, and then it will be really hard to make your next stitch because it's so tight. Just pull till it’s the size of the shank, after doing this, repeat till you have as many as you need. This stitch is known as the chain stitch, chaining, or by the abbreviation (ch).
Once you have a chain (I'd suggest 15-30 for a potholder, depending on the size of the hook, and yarn) you need to be able to go back, so, when you figure its as long as you want it, flip the work over, so that the back is facing you. There will be a series of 'V' shaped holes, with two separate strings, if you want your 'work' to be reversible, I'd suggest going through both holes, though some people like the look of only going through one; on your first try, I'd suggest trying both. To turn and successfully make a flat edge, you chain one extra, and skip the 'first' stitch (not the one you just made), this will make it lay flat. In the next hole, you push the hook through the 'V' either one or two of the strings, and wrap the yarn around the hook like you did to chain. Pull the hook back through the work, and finish the stitch by picking the yarn up again, once, and pulling it through the two pieces of yarn on your hook. Please note , that for every stitch except the chain stitch (an other special ones that are noted) you will pull your yarn through every set of two strings. This stitch is known as a single crochet or by the abbreviation (sc).
Once you single stitch or single crochet (the same thing) all the way to the end, you turn in the same way you did with the chain stitch, turn the work around (which should be more obvious now) and chain one, skip one stitch, and continue. If you wish to change stitch types, or yarn, it is the best to wait till the end of the row. Even if you run out of yarn, it is best to rip it out (to the end of the row) and start the new yarn there, it looks so much better).
Double crochet: This is just like single crochet, except, before you stick your yarn into the hole, you wrap it once around the hook. Once wrapped around the hook, stick it in the next hole, pick the yarn up once, pull it through, pick up the yarn once more, pull it through two loops, and then another two. This is a double, also known as (dc, or ds)
Triple, or Treble: This is the same idea, except before you stick it into the work, you wrap the yarn around the hook two complete times, then enter the work, pick up the yarn once, pull it out, pick it up once more, and complete three sets of two. This is known by the abbreviation (tc). Once you get the hang of it, it very easy, very quick stitch, but it tends to be a little flimsy. You size double and triple crochet the same way you do single and chain.
Changing Yarn: The best way I have found, it to cut off the yarn your using till you have an 1" or 2" tail, and pull it through the hole securely, it shouldn’t come loose. Then attach your new yarn by slip knotting onto the shank, and single crocheting off of the already existing work, its seamless (for the most part) and you don’t have to worry about your knots coming loose).
The end of a skein: Yarn comes in balls and skeins. And skeins in particular can be really annoying toward the end of the yarn. It is always best to start crocheting from the strand of yarn that comes out of the middle of the skein, that way it doesn’t roll everywhere. Well once you get to a certain point (trust me, you'll know it once you get there) you'll want to ball the rest. Well you don’t want the ball rolling all over the floor when you draw yarn, it gets dirty that way. So my grandmother taught us how to make a ball that feedsfrom the middle. What you do, it take the string that you are working with, and stick it in the middle of a pill bottle. On the out side of the bottle wind the rest of the string, starting from the end your working with, all the way to the end that your not =) and slowly remove it form the bottle, and you have a ball that feeds from the middle. Very handy.
How to read sizing on patterns: Patterns don’t always give you a specific amount of chains to stitch to form the base, but many are dependanton having a specific number of chains so that the pattern will be even. So, the person who created the pattern usually includes something that looks like this: 10x12. This is the sizing reference. What it means is that, you have to chain a number of stitches that is divisible by both 10 and 12 in this case. Here 180 will work (but I wouldn’t recommend 180, its too long).
Count your stitches: It is also important to remember to count your stitches when you are done with a row. This will help keep it from looking like a bowl amoung other things.
If you need more help, ask your grandmother, a friendly lady at a nursing home/senior center, OR consult a book.
For more info check out: Yarn