Besides working at co-op or summer jobs, here are additional ways you can build your computer science-related skills and experience.
Work on problems and challenges posted on websites such as MindSumo, Project Euler and HackerRank. MindSumo is a site where “college students tackle company projects for experience and cash”. Project Euler is “a series of challenging mathematical / computer programming problems that will require more than just mathematical insights to solve.” HackerRank is a "learning and competition community for programmers".
Take on short-term gigs or freelance positions in technical areas of interest. Look for these opportunities on websites like the local Craigslist computer gigs list, or via freelance site such as Upwork.
Volunteer for a non-profit group needing technical assistance (e.g. help with their website, app development, or redesigning their donor database). You can find these volunteer postings on UBC CareersOnline, at govolunteer.ca, or on the UBC CS student job postings site. You could also search the Red Book Online to find non-profit organizations of interest to you, and contact them directly about possible volunteer work.
Ask your professors if you can volunteer to help them with their research projects.There are many different UBC CS research labs doing a variety of projects. See here for links to the labs and research areas.
Work on personal projects and then put them together into an e-Portfolio. This shows that you have both initiative and technical skills. Many employers now ask for links to samples of your work as part of their job applications process, so having your e-Portfolio ready makes this easier.
Take part in hackathons and game jams as a way of building your coding and teamwork skills.
Study programming languages on your own.There are lots of online tutorials, books and websites available to help with this. The ICICS Reading Room is a great resource for this as well.
Attend meetups about technical topics that interest you. There are many, many technical meetup groups in Vancouver, so start by searching here. Meetups often have both a presentation about a particular topic, along with a time to network with fellow attendees.
Prepare for technical interviews by reviewing some of the resources available through the UBC ICICS Reading Room or by practicing solving problems on LeetCode.