Direct Complimentary: This color combo uses two colors directly across from each other on the color wheel. In this case its yellow and purple. When you have opposites it really highlights the differences between the two colors, so this room really allows the colors to pop. Also, because they're opposites, purple helps balance the irritation that yellow in large amounts can create.
Analogous: This color combo consists of 3-5 colors that are next to each other on the color wheel. Its like using a section of the rainbow and it is a really smooth color scheme because the colors kind of flow from one to another. Very peaceful.
This room uses yellow, orange and red:
This room uses yellow, green and blue:
Monochromatic: Using too much yellow can be unsettling. So you have to be careful with monochromatic, because all that yellow can be overwhelming. That is why I love this bathroom/shower curtain by Elle Apparel. It uses a lot of whites, creams and light yellows as well as the more bold and darker yellows. This keeps the yellow from hurting your eyes and taking over the space.
Accented Neutral: This is almost always my favorite color combo. When you have a neutral space, you can use pops of color to add interest and then if you want a change, you can easily switch out pillows and art in a different accent color and you have a whole new space. A really hot color trend right now is yellow and gray and I just love the way its used in this room.