When it comes to color, when you are young you can experiment. So have fun with it. If you are older, the general idea is the lighter your hair, the less severe it will look against your aging face. So do lighten up a bit. Highlights around the face are amazing. There is nothing to prevent you from trying to color your own hair at home. A haircut may set you back a bit, but hair color can be done very effectively at home for $10.00. Naturally, if you love being gray or white haired, then that's great! And lovely too.
Hair no nos: spiky hair, ridiculously long hair, helmet hair, black hair if you were not born with it; roots, especially gray ones; Louise Brooks hair after 25, ashy blond hair for most skin tones.