Do you like two tone hair color style? I love it!
I usually go for a natural option: letting my own hair grow to add some dark blonde roots to my lightened tips. I used to this natural ombre since my own hair color is not that dark, and that creates a pretty gentle gradient.
There is one pictures' set I've made for you. The set of cool double hair color ideas, which are the trendiest this season.
Except the typical ombre (which, I believe, is already used by every modern girl), there is another two tone hair color option going trendy these months (thanks, as well, to Harley Quinn): a vertical coloring, when right and left part of your hair is dyed with different shades.
I can't say I would like to try it, that is too extreme for such a conservative minimalist lover like me. However, I absolutely enjoy watching this hair color style in looks of other girls.