Are my pictures any good, and how can I imporve them?

The best thing to do would be to take a college level drawing cl. If you're in high school you might be able to find community college night cles for fairly cheap. If your really want to learn to draw well it's absolutely necessary to have a teacher, preferably one who knows what they are talking about and can help you in real time WHILE you are drawing. It's worth every penny.