I've been adding sort of a racing stripe on my borders. On yours as a suggestion only a 2-3" border in the background fabric, then a 1.5" stripe in a color you want to stand ut and then finish off with a larger background border. Been doing this for my last couple quilts and really like the look. Plus for those quilts that just need a little more size added to them, this works..........at least for me it did.
Love the colors in your quilt, so bright and cheerful. Put on the sunglasses...:-)