Hair ideas

So right now may hair reaches just below my shoulder blades and I think I want to cut it shorter. 
It's pretty straight, and a middle brown color but I'm thinking of adding some red (like a natural red color not an obnoxious red). 
I have really fine, thin hair but it's oily and flat very easily. I know the best thing I can do with this type is probably to cut it, but I'm not sure how. 
I don't want it to be like a pixie cut or like super super short, not above my ears I guess. My face is round so I feel like a very short cut would not be my friend.
Anyone have suggestions as to what would work? I'm awful at hair!