I think a good way to pick your colors is to find something you love (perhaps a favorite painting, rug, etc), like an inspiration piece and work with those colors. Or, if you already chosen a theme, work within your that color scheme (tropical: oranges, reds, greens; beachy: sand, blues, greens, etc) Also, I think it's really important that the colors you choose flatter you and your fiance as well as the bridesmaids (skintone wise). Good luck!