I pull from focus fabrics to make sure that the colors coordinate. I've had varying success rates. The celestial circles quilt on my blog has too many fabrics in the same intensity so the purple circle doesn't pop as much as I would have liked (I'm also very glad that I decided on yellow for the other circle rather than the red as I would have lost both circles.
I'm hoping that using yellow in the border might change some of the visual impact.
The yellow in the penguin 9-patch (also on my blog - below) is a little yellower than I'd like - it does coordinate well, but I think a slightly more of an orange tone would be better - however, now that the center is pieced, the bumble bee effect is lessened.
On the other hand - the Dragon Quilt (August 2010 in the blog) came together really well in terms of color and contrast - I didn't have a fabric collection to work with like I did with Celestial Circles and spent a lot of time in the quilt store auditioning colors and patterns. I'm in the process of piecing the border and hope to start adding borders soon (working my way through Quilter's Academy and I haven't reached the borders class yet).
Cheers, K