I have only knit one pair of socks so far, so I am by no means an expert. There are lots of experienced sock knitters here on KH though ... so maybe one of them will have more detailed tips for you.
I would start by watching the video on working the heel of a sock on the video page. There are also lots of other great videos and tutorials out there .... I would recommend checking out Silver's Sock Class
, I found it very helpful in grasping the new concepts involved sock knitting! Follow the link and scroll down to select the tutorial that is designed for the method of circular knitting that you are using (eg. DPNs, 2 Circulars, or Magic Loop).
Hope this helps you get started!