I'm not sure I say there are necessarily any "tricks". There's a lot of the usual stuff like having an updated and clean resume that presents your background well, having previous job experience, etc. Apply to jobs selectively that you think you are qualified for - don't apply for everything under the sun in their job postings. You'll also want to make sure you are physically in Canada at the time you apply in case you are called for an interview. (If you're not in Canada now, I would hold off applying until when you return). It helps if you are mobile - i.e. potentially willing to relocate to other parts of Canada if needed. Aim for entry level jobs and temporary jobs to get your food in the door. Your first step may be an entry level job that isn't your ideal job (e.g. call centre, census taker) before you may be able to secure a job that you think is more ideal (e.g. Service Canada - this would be the person handing out SINs). As said before, there is a lot of competition for these jobs.
I would also say that the Service Canada job you saw at the airport isn't necessarily all easy. There are occasions where these people get yelled at or where they deal with very difficult people looking for
Taza Jobs. This is a front-line job from that perspective so it would require and involve the ability to manage difficult conversations, diffuse anger, deal with confrontation, etc.
Hope this helps.
