Of all the directions of light, perhaps there's no finer option than shooting directly into the sun. This is particularly true when working to emphasize color. When lit from behind, your subject will appear to glow. If the contrast is too great, eliminate the sun from the frame. This will make for a more even exposure while still providing the dramatic benefit of backlighting. If you're not comfortable with metering manually, take several shots using exposure compensation. Bracketing this way is a quick way to handle an otherwise tricky scenario.
For added impact in your outdoor photography, consider using complementary colors. Although blue and yellow reside on opposite sides of the color wheel, they can be used together with outstanding results. On one side of the spectrum, blue is ideal for creating a quiet introspective mood. Warmer tones however, will infuse your subject with a dynamic energy. Each are effective on their own, but when used simultaneously, the contrast will bring attention to your main subject.