I was thinking about doing that same thing, not making enough at my day job. Took a bartending class and got my license, but no bars/restaurants want a bartender without experience around here (I’m assuming it’s frowned upon anywhere). I’m thinking I’ll have to start as a waiter first and work up to bartending, hopefully it won’t take too long.
I would think of which job you could get that paid the most, there’s a lot of part time jobs that have good hourly wages. Have you tried working at a pool? Lifeguards may be paid decently around where you are but managers and swim instructors are probably paid even better. Classes to get the licenses are easy, assuming you can swim, which is also easy once you get the hang of it (as someone who works out, that is, if you’re out of shape, you’ll get very tired very quickly). And around here, there’s always open positions for pool workers. I think refs get paid pretty well, too. You can find a local rec league for whatever sport you want and just take a quick referee class (some may not even require that). I’ve never done stocking/unloading jobs (not as an actual job, have had jobs where that was one of the tasks we had to complete) but sounds good too, as long as they don’t pay minimum wage or barely higher. I’d be more inclined to find a job that isn’t monotonous myself, I don’t know if I could handle just loading and unloading boxes all night for 3 or 4 nights a week, but to each his own.