Wardrobe for your eyes
Shades of orange, red and yellow will compliment your blue eyes; shades of blues and purples will enhance your blue eyes.
Shades of orange and red will compliment your green eyes; shades of green and purples will enhance your green eyes.
Brown being a natural color you can get away with anything; but warm hues like red, orange and burgundy, as well as blues and purples will make them pop.
Like brown, gray is also considered a neutral. Gray eyes look great with black clothing. The contrast of light and dark will make your eyes pop; and since black is also traditionally neutral, it won't overwhelm the lightness of gray. Also, it's very likely you have either a green or blue hue to your gray; if this is the case, follow the rules for those eye colors accordingly.
The choices that apply to green- and brown-eyes also apply to you. Purple, green, brown or orange, will pick up similar shades in your irises and bring them out beautifully.