depends on what you need. i needed a lot of flexibility, so i kept my regular job, and just decreased my hours to a manageable level. i had a good relationship with my boss, so they were willing to let me do that, and worked around my ever-changing class schedule without complaint.
in retrospect? i wish i had applied for a job as a phlebotomist! a friend of mine did that. she worked from 3:30am to 8:30am and then came to class. she received a ton of experience that i totally envy.
otherwise, it just depends on what your personal situation is. are you looking for experience, just need a decent income, a flexible schedule, etc? the suggestions you've gotten so far are pretty right-on.