I've had a couple of jobs here and there, most have been temporary which suits me as I get bored quick and sometimes I may just be looking for money for a couple of months.
I had a small job cleaning plates/setting the table in a small pub, I've worked at my old golf club (doing multiple things) and recently I worked in Boots. I didn't mind them all that much, it's money, it's experience, it helps your confidence, and you can meet new people. Of course I had those days where I couldn't be assed getting up at 7:00am when it was ice cold or when you're working an 11 hour shift offloading pallets of stock and helping rude customers, but overall it's good. I guess I've been lucky that I've been in good work environments, a lot of nice people, and people my age who I can talk to.
For tips on the interview I'd say come across natural. I'm quite outgoing and I've been lucky in that I've had interviewers that I've had a bit of banter with. So maybe if you're nervous or shy, I'd say make sure you know the fundamentals. You don't need to know everything about your job, but know what it entails because they'll ask you tricky questions. If your job involves customer service, remember that the customer is always right and make that clear to the interviewer. Also try and show a bit of energy and charisma, I haven't always been the most prepared or most qualified, but I like to think my personality helps. Oh and another thing, show ambition, and be flexible, interviewers will more likely take someone who can adapt to any kind of working hours than someone who's only available a couple of times a week.
Good luck.