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.
Thinning hair? Did you know you can make it appear thicker by the strategic use of color? By that I mean if you color your root line to deal with any regrowth you're also making the roots look a bit darker. Not only does this touch up your color it will also create the illusion of thicker hair. That's because roots that are a bit darker make your hair appear to be fuller and more dimensional.