If I'm avoiding using a color, I'll look at the color challenges here. They always have good ideas for using colors that I didn't otherwise like. For example, I didn't think I liked bravo burgundy. There was a color challenge using bravo burgundy, pretty in pink, and always artichoke. Now, I'm sold.
I do have the color wheel and use it on occasion. Most of the time, I just gravitate towards what I feel like using at the time, though.