Thank you so much for the detailed response! I suppose I should start taking a deposit because I doubt my good luck will continue. Thus far my clients have been wonderful people and excellent about staying in touch and paying in full. It didn't occur to me not to send good process shots though, so thanks for the tip there.
The reason I offered commissions this summer was to see if I was ready or not. I wanted to know if I could offer a product someone might buy (aka is my skill high enough?), and if I could complete it fast enough to keep the cost reasonable (because I'm absurdly slow). I've reached a point where I can get a good drawing done in a reasonable amount of time, but now it's a matter if I am good enough for clients. I had two jobs and a community theater project over the summer that kept me quite busy, and I found it was really a drag to sit down at the end of the day and work on someone else's drawing. For some reason, once drawing becomes work I feel much less motivated to do it. I learned this about myself in high school and promptly changed my life plan from being an illustrator to something else as a result. Next time I open commissions (because as nice as the idea of doing art for art's sake is, I'm broke D: ) I'm going to set aside specific amounts of time where I draw and treat it like a job and see if that helps me 
I also understand the importance of reputation, and to make up for my last commission taking way too long, I'm giving them a free drawing 
I also understand the importance of reputation, and to make up for my last commission taking way too long, I'm giving them a free drawing