If you're on the waitlist
Movement happens — sometimes in waves through May and June, sometimes as late as August as accepted students decline offers, defer, or shift to other schools. There's no schedule and no predictable rate. The most useful thing you can do is keep your contact info current with OMSAS and respond to any communication within hours, not days. The hardest part is the uncertainty; the practical part is just being reachable.
If you're moving forward as if you'll get in, the rest of this guide still applies — start the financial homework, look at housing, and treat the waitlist as a strong probability rather than a coin flip.