Cowgirl
I would sure try a lighter thread and shorting your stitch length. When I look at something I like to see the leather (tooling ,Stamping or in this case the color and design) before I notice the stitching.I would also try and get some colored thread to match the leather you are sewing, that is not always possible to do. I like your designs and it looks like they will work nice as well. These are just things to try and work at.
Great job Mark