I have knitted a few pairs of socks from the patterns on the net and in various magazines. My problem is…they don’t fit! I wear a size 13 shoe and whilst I can knit the sock any length they are still too tight around the actual foot. How do I adjust a pattern (or where do I find a pattern) so thet it fits me?
Here is a sock pattern generator
http://violetgreen.co.uk/sock_pattern_calculator.php
Also, 2 books, Sensational Knitted Socks & More Sensational Knitted Socks have charts to make it easy to measure your foot and figure out how many you need to cast on.
You can adjust the pattern by working the gusset decreases a few less than called for in the pattern.
For example, if you worked the leg over 72 stitches and the pattern instructs you to work the gusset till 72 stitches remain: stop working the gusset at 76 or even 80 stitches. This will give you the extra width you need in the foot; an 80-stitch foot is wider than a 76-stitch foot, which is wider than a 72-stitch foot, etc.
If you are continuing a pattern on the top of the foot, you may need to tweak your numbers in the multiple of the stitch rather than in four-stitch increments. For most of us, an increase of four stitches for a wide foot (or a decrease of four stitches for a narrow foot) is sufficient, but you may occasionally need a bigger difference. 
Hey, thanks so much for all the great ideas. I do appreciate it!
Rene
http://home.earthlink.net/~bruxknits/pats/BasicSockChart.pdf - best sock link I’ve ever used!
A sock is usually a tube with a heel put in over 50% of the stitches (sometimes more especially with short-row heels) and of course closed at the toe end. If you want to make the tube bigger, either keep the stitches the same size and add more stitches, OR keep the stitch count the same but make the stitches bigger, OR increase both.
(Denise’s example applies to top-down socks).
Basically, measure your foot and your gauge, and choose stitch number based on that. The general rule is cast on enough stitches for about 1-1.5 inches less than the circumference of your foot (because if it were the same, the sock would be too loose).