You wouldn't wear a tie that has colors in your suit (come on? black tie? grey/navy tie? no.). Depends on what kind of shirt you're wearing. If white, pretty much anything goes that isn't hideous, but if it's a shirt with a pattern (like pinstripes or somtehing), you can pick out a color that exists within that pattern. This is one of those personal taste things, don't freak out about it. If you're feeling really stumped, go to jcrew.com or bananarepublic.com to their mens section / shirts/ties to see how they've created their outfits and matched ties.