There's so many questions when thinking about knitting your first pair of socks - will they fit? Do I do top-down or toe-up? What yarn? What needle size? What pattern?
One of the best things to do is jump in there. Most first pairs of socks don't fit the first time, but there are a lot of lessons to be learned because everyone's gauge is different and everyone's feet are different. Try different patterns, different needle sizes until you're happy with the end result.
Most people have good success with size US 0 or US 1. I recommend trying both toe-up and top-down to see which one you prefer. A good top-down pattern is Vanilla Latte Socks by Virginia Rose-Jeanes, available for free on Ravelry. A good toe-up pattern is Toe-up with a Fleegle heel, also available for free on Ravelry. It's good to try the different heels and see which one you prefer.
Next for yarn. The best sock yarns have at least 15% nylon. This gives them strength. Some of my favorite sock yarns are Candy Skein Yummy fingering, Ryberry and Fibrelya.
Now you're ready to start! Have fun and before you knowit, you'll have a pair of hand knit socks to enjoy.