Is your hair healthy enough to withstand the chemical onslaught some coloring products produce? Or could it use some TLC before you step up to a new color?
A good color means natural. Look carefully at a fistful of hair in the mirror. See how each strand has a different tone? Perhaps even different colors on one strand? These are the natural striations that Mother Nature gives each head of hair to work with natural lighting. A good "color job" must duplicate these natural highlights to be effective.