Did this (in several universities where I studied):
- taught part-time on campus as an assistant for several classes (during the day),
- taught part-time on campus as adjunct lecturer (in the evening),
- worked part-time for a startup created by someone from uni (likelihood that it's close, and flexible with your student situation),
Boring, not well-paid, but easy to do, comes up regularly, and you can sometime manage to read or do some work during the exams yourself.
did paid internships,
- did ponctual contract-work for a software marketing company (doing demos in malls and stuff for new software releases on week-ends),
- taught private lessons to middle-school and high-school students (CS and non-CS related courses),
- did unpaid lab-work (but it helped to get other jobs),
Worked my university's junior entreprise.
Junior entreprises are student bodies that finds jobs for you, and which draft the contracts as an intermediary: you're legally covered, and usually decently paid, for jobs that mostly relate to your field. A lot of universities and engineering schools have these.
My universities / engineering schools where quite student-work friendly. We were actually forced (it was part of the grade) to have 3 6-month internship during our 5-year program: one after 1st year, a 2nd after 3rd year, and a 3rd one after 5th year. You can make a decent amount, and you get out of uni with some experience.
Add part-time work to that, and you look pretty employable for a graduate when you have a pretty filled resume for someone who just graduated.
Do think long-term if you can: you're building contacts and a resume, so make sure, if you have multiples opportunities, to pick the ones that will consolidate your resume.
Also, look for jobs that specifically target students, and where they won't request tons of experiences, like call-centers (did this in high-school: crap job, but in high-school you don't mind the low-salary) or jobs where you stand and run a lot, like that demo company I worked for. They employ mostly students and do all leg-work for you: it's contractual and ponctual jobs, you have a one-day presentation of the products for free, they send you the products (which you can usually keep when it's games and software, not so much when it's hardware) and then they find you the placements for the week-ends. You just need to show up wearing whatever attire they recommend, and sell stuff.
Other Possible Options
There are other options, that I didn't pursue out of lack of time, because places where limited, or because they weren't my cup of tea.
Many universities employ students as part of their IT workforce. Good to get experience, they can get you out of some exams or get you to substitute a school project for a job (though sometimes you get stiffed with a lower substitute mark for a project you'd have aced).
Either privately (post ads on yout school's boards) or as part of a student body.
Some labs in your school might look for assistants, and sometimes they do actually pay. If you find one of these, and they don't overwork you like a dog for a miserable pay, leaving you exhausted for school and unemployable for other thing, hold on to these. Great experiences.
Many startups are created by students or recent graduates, and they know what you deal with. Careful though: startups die. They often do, that's the harsh reality of it. So you can end-up without payments.
IT support for small local business (local printing shop, doing websites, etc...).
- Non-tech jobs close to your home or uni, even craps ones (food-court and stuff).
- Night-jobs pay well, and may leave you tons of time to read or code, depending on the type of work, like night guard for companies in quiet areas (just don't overdo it, good stuff for one-time payments, like a supermarket inventory).
- request payment for family IT-support tasks.
- Create small apps on iOS or Android and sell it on an app-market, or any kind of easily marketable software. Or get micro-payments with something like Flattr, or ads from websites you create.
Avoid as much as you can (got some friends crippled by these). They're nice as you get a bundle of money but you'll need to manage it correctly (and will probably fail, to a certain extent) and to reimburse this with nice interests for the next 10 years. If you played your cards right, or it will be way worse. I repeat and stress it: avoid as much as you can!
Great, if you can get one, but careful: they don't exactly come for free most of the time as many imply volunteer work at school. There are multiple types of scholarships: the ones offered by your university (mine didn't have any), and some sponsored by your state or local government. These aren't often very advertised, but you'll find them online, and by going to your city hall and other places where you can get student help. Prestigious scholarships (they aren't all like that...) can be a plus on your resume.