So I spent a few minutes making this tool to help create basic color palettes fast:

http://www.newgrounds.com/dump/item/2fd1ebc90a376bb8e43315d0014a4c8d

In order to use it you have to slide the obnoxiously tiny, almost entirely transparent arrow you'll find at the bottom of the bar to the right of the circle. Rotate the teardrop until it "points" to the main color you plan to use; all the colors  inside the drop will be more or less fair game for you to use in the same image.

**You'll have to print screen or something if you want to save your palette.

Keep in mind that there's no science whatsoever here, and there will probably still be colors you'll find inside the teardrop that will look like shit. User discretion is advised.