Some of the best FRC websites I have seen are from Teams
1114,
254, and
610 (and a shameless
3476 plug).
When it comes to website design, pick something to match your experience level. I would start off simple before going too complex. A good library and platform to start off with is
Bootstrap. There are a lot of examples, and its easy to get a professional looking website set up quickly, but it has enough freedom to let you go your own direction (its also compatible with mobile browsers out of the box!).