The second stop on the internet is an Expert's page....most likely to be on lifestyle web sites which tell the ground rules of which skin types goes with which hair color etc. Don't bother to read too many of these as each one of them is likely to have their own version of hair color palette! Once you have short_listed a range of hair color options, try looking for pictures of people with similar coloring and how they would look in it. Many salons have sophisticated software which helps conjure up an image of you with the hair color and it might be worth the money you spend on it.
Coloring tip: It's a fact. The longer your hair is the older the ends are. Okay no news there. What may be news is that this makes them more porous and open to accepting hair dye. Which is why you want to get to them last if coloring at home. Otherwise they may end up darker than the rest of your strands leaving you with a final result that is well, interesting looking. Just not in a cute and sexy way.