I always fell back on waitressing, in a restaurant, whenever I needed extra money for a multitude of reasons. First and foremost it was cash every day--always my main reason for part time work. Then they also feed you, usually for free or at a greatly reduced rate. It's a relatively safe environment to work in and you won't stand still long enough to get bored. If the restaurant has a banquet room then there's the opportunity to work a banquet that usually means a really big tip (figured in automatically by the restaurant) with not a lot of work (usually a restricted menu or one where everyone gets the same meal).
There are drawbacks. It can be very tiring and your feet will hurt. Depending on the restaurant you might be held responsible for a bill that a customer skips out on. That can be devastating but if that happens the other people working will usually chip in to cover the tab.
You might make more money in a bar rather than a restaurant but the clients are different and the attitude toward the wait staff is different. While you will probably be able to find a job without experience be prepared to work the bad shifts or split shifts until you learn what you're doing. It doesn't take long to learn and it can be fun.
One time I was trying to serve wine to a couple on what was probably a first date and instead of placing the glasses on the table and pouring the wine I poured the wind in the glasses while they were on my tray. (Yes, this was my first serving of wine) I got the first glass down okay but when I went to put the second glass down the hand holding the tray tilted in the same direction as the hand placing the wine glass and the bottle of wine ended up emptying itself all over the guy. Life stopped! I knew I was in trouble. Then his date started laughing. Then he started laughing. I started apologizing all over the place but they were adamant that no harm was done. They finished their meal and left me a really great tip. I figured the incident broke through the first date awkwardness and that's why they weren't upset. Whatever it was, it worked out well for me.