Tutoring is always good. Especially for high schoolers now that APs and SAT IIs are coming up. You can make more tutoring privately or work with a tutoring company for more consistent hours.
Seriously! Do some sleep studies. The long ones pay 7-10k per month. What this means, however, is that you will be locked in a hospital/research area, unable to leave, for a month. That said, I would do 1-2 of these studies, and kick back for the remaining time!
I graduated in December and got a job for 8 months waiting tables. Of course, I had 5 years of experience, but it isn't hard to find a restaurant that will hire you. Personally, I would tell them about going to medical school (I did). Not only are you being honest, but that employer will know you're intelligent and a hard worker. If you go into the service industry, 7 months is a long time since there is such a high turnover rate.