Hi Nicole,
You could try planting one solid color next to a multicolor that has the same color in it. For example: The yellow color in 'Ming' pulls out the yellow in 'Tripod' :
Also, pairing pastels with pastels looks good; and saturated colors with other saturated colors is good.
I also like black irises with about any color. This is cut flowers, but it gives you the idea:
The trick is to find irises that bloom at the same time. May require some trial and error!
Good luck!
