I don't have any problem putting colors together, I probably tend to make things to matchy-matchy. My advise would be to lay different fabrics side by side, switch them around, take your time looking at them. I am right now trying to decide on 5 different blues, from dark to light, for a king size dresden plate quilt I want to make for myself. I also take swatchs to the fabric store when I need to match something.

Me too! I usually look for a whole collection and figure that anything I pick from that will work. Here is one I just did for a charity auction tomorrow. It is a jelly roll and then some yardage from the same collection.

Very carefully! .... And I've been cautioned about picking everything from one line of fabrics; they'll all blend, but you may lose the individuality of your own creative juices, like using a cheater fabric (which I've also done on a few occasions when time was of the essence!)

I definately don't ask for advice from the woman in a gaudy blouse, wearing way too much perfume and capris that clash who's husband is quietly protesting being hauled along wearing 2 different plaids with a base color of mustard yellow

To make the colors harmonize, I pick them from just half of the color wheel.
I find white or light shades very distracting and difficult to use with many bright colors, so I leave them out to use with a pastel color scheme.
Unlike the rules of putting lights and darks with mediums for everything is - I DON'T. The attractiveness of the 30s colors is because they are nearly all the same value bright colors.
Black will make bright colors pop if it is used as a background or sashing.

I am terrible at choosing fabrics. Probably why I like scrap quilts so much.

I don't have any rules except if it looks good and I like it then that's what I use. Have a girlfriend who has to match everything. The quilts look good but not my cup of tea. Mine are bright with lots of movement and some fabrics that don't seem to match but they look good when finished and the recipients like them too. ~ Chris

This sounds interesting. I think I'll try this one. I'm not for matchy-matchy either. When I was in high school, a few of my "matchy-matchy friends thought I was a bit weird. Now, since the 50's colors have come back into vogue, I see those same people WEARING THOSE COMBINATIONS.

I pick one fabric I like (focus fabric) and use it to pull colors from, ignoring the prints except to be sure there are a variety of print sizes.

If I'm not sure I think the colour is right, I take a photo of the proposed fabrics, and it seems to give you a better perspective.