Chukk, I'm very proud of you for taking some time to create something and put it out there. I have tons of respect for anyone who takes the time and effort to put their money where their mouth is and actually make something. There's a lot of big talkers who'll never accomplish what you did because they're too busy talking while you were busy creating.
I could go on and on about specific critiques, but here's my number one piece of advice I want to impart. Practice. If you want to get better, just keep working in RenPy, keep writing, keep creating. The more you do it, the better you'll get at it. Promise.