To begin with the choice of colors would top the list. So what family of colors is on your mane wish list? Are you looking to alter the color or color the gray?
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.