The only suggestion I could give would be to try a "saddle stitch" next time. It's a little sturdier and less prone to unravel than the standard stitch you have now.
Looks good. Read through the tutorials on this site and try to plan it out as much as possible. Before you know it, your work will be top notch. Just remember to keep it fun. If you start to get frustrated, walk away for a while.