Make sure you have your white balance set correctly. Each lighting condition has a different color, so make sure your camera is set correctly for the light that you are shooting in. If you have a regular digital camera there is usually a setting to choose this, for example shooting in the sun, or shade, or inside. If you have a DSLR you can set a custom white balance. Read your manual to find out how.
After your white balance is set correctly make sure your exposure is correct. You don't want to over or under expose your picture. The easiest way to get the right exposure is to focus the picture first on the place in the image where you want to be the most in focus and the best exposed. The camera's internal light meter should do the rest...
