Are you ready to start knitting along with me? We'll cast on for our toes next Saturday. While we're waiting, let's choose the best possible combination of yarn and needles.
I actually have three of these sets of Knitpicks double pointed needles. They come with one pair in size 0, two different size 1s, two different size 2s and one size 3. I absolutely love them, but if you don't do a lot of knitting with different weights of yarn, they might not be the best choice. I find myself using both size 1s and the smaller set of size 2s for my socks and, less often, the largest and smallest sizes for other things.
Using worsted weight yarn? Start with a needle two sizes smaller than the ones you use for your regular worsted weight projects.
With the needles you think you'll be using, cast on twenty or so stitches and use two needles to knit yourself a swatch. Knit a row, then purl a row, then knit a row....On the actual sock, you'll be knitting around in endless circles, but for this you need to alternate to get stockinette. Knitting back and forth in rows won't give you the exact same gauge that knitting in the round will, but we're just trying to make sure that this combination of yarn and needles will create a fabric you like.
I used size 3 needles and sock yarn for the beginning of this swatch. That's way looser than I want the fabric of my sock to be. After the garter stitch ridge, I went down to 1 1/2s (I think -- they're not labeled, but I've used them for lots of pairs of socks) and got much more suitable results.
You want a tight knit. With sock yarn, that's probably going to be 7 or 8 stitches per inch. (You don't need to measure and count unless you really want to!) If your stitches are too loose, the socks will be uncomfortable to walk around in and won't hold up as well as tighter knitting will.
Stretch your gauge swatch a bit. If there's a lot of empty space visible between the stitches, they're too loose and you can go down a needle size. If it's too tight, you're probably going to feel it while you're knitting. I've actually heard that you can't make your sock gauge too tight, although I'm sure you could if you tried hard enough.
Socks don't have positive ease like a sweater does. The circumference of the finished sock should be the same or a little smaller than the circumference of the food that will be wearing it. Your store bought socks are probably that way, too. Notice how they stretch a bit when you put them on?