As I started to dress better, I too became increasingly aware that my sock game needed to match everything else. Rather than white socks now, I bought a bunch of navy argyle dress socks and wear those most of the time, even casually. Since I wear jeans from medium dark to dark, or something like khaki or grey chinos, and brown shoes of varying shades the majority of the time, they seem to go pretty well with almost everything I have. I've gotten a lot of compliments on them too on those rare occasions when your sock shows more than usual. I need to go get some more patterns and expand a little to make it more interesting, but I just haven't gotten around to it. So something like that might be a good place to start.