The problem is, you can't take the practice board for granted. Practice means practice, not wasting time. The practice board is meant for gettubg used to the tools and really trying to improve. If you really put effort into your drawings, you'll get much better, and you're pictures won't be deleted! I mean, most of what I draw isn't very good, but I'm constantly trying new things and trying to improve, which means putting time and effort into every drawing. Thus, most of them aren't deleted.
So don't get discouraged, just keep working at it! Yes, it's a practice board. Practicing is what it's here for. If people can tell that you're putting effort into your drawings, they'll help you improve. People here are nice, you just have to get on their good sides! ;D