The whole idea with red is that you either go big and make a bold red statement, or you use just a little to accentuate your design. Above see Maryann (like Gilligan's Island). It's all about the red, suggesting a sensuality and an innocence at the same time. Below see Magdalene, I used garnet to highlight olive jade and copper links. It's just enough to make the design pop.
I actually really like organizing by color. I often wonder if that would be an appealing way to sell and display my jewelry-only by color. I dream about having my closet organized by color, but then it would have to be organized!