1. Always, always, always make notes of how many rows, increases or decreases, yarn repeats, or anything else while knitting the first sock. I guarantee you that you won’t remember when you start the second one.
2. It’s a pain in the butt at first, but somehow or other, learn how to Double Cast-On (aka Long-Tail Cast-On) (aka Continental Cast-On). It is such a neater cast on than knitting on and makes your cuff much nicer looking and stretchier to boot. I didn’t think that it mattered so much, until I compare DD’s socks to my first 2 pairs. HUGE difference!! If you would like to watch a video about this cast-on, the link is HERE. There are lots of other video instructions on this site — look around a little. (I first read about how to Long-Tail Cast-On in my Stitch-N-Bitch Handbook — which is money well spent if you are thinking about buying any knitting book — lots of knitting tips, explanations and humor. The gal definitely knows her stuff!!)
3. Check that gauge!!! This is another thing that I wasn’t so sure mattered so much — well, it does!! It’s also a pain in the butt, especially when you are chomping at the bit to get started on your sock, or whatever you are knitting. If you are knitting socks, check your gauge in the round, not flat – makes a huge difference.