Second, use similar color tones. If you have more than one piece of art in the room, use the same color palette. Use brights with brights, pastels with pastels, moody with moody. It's not the subject matter or even the frame that's important to a cohesive look, it's the color of the art. Each of the rooms below show cohesive colors, even though the subject matter and frames are different.
If you use these tips and when buying art that you love, you will have a wonderful art collection that you can display with confidence.