At Joann's, I find that other shoppers are the best for help, including color opinions. I must have a friendly face because it's rare that I'm NOT asked a question when I'm there, and I've gotten helpful hints there from other customers too.
I love picking out fabrics and colors, either I'm just not picky or I have an eye for it because I rarely have trouble coming up with a color palate. My trouble is picking between so many options! But I really like a ton of colors - when it comes to quilts there is no color that's off the table for me.
I have taken some art classes, though - none specifically about color, but enough that I've studied basic color combinations and painted out my own color wheel using only primary colors that I had to mix myself. I keep thinking it'd be a lot of fun to make a scrappy color wheel out of fabric for my sewing room but I haven't gotten around to it.