My site is on the first page when search "job search toronto", "job search vancouver","job search ottawa" on google.ca.
But my traffic doesn't increase. any idea how to track search engine traffic?

There are not many people around searching for "job search Toronto" according to wordtracker.com, only 21 searches. Try to optimize your site for more competitive keywords like "job search", "job listings" or "jobs". I know its harder thing to do, but if you succeed you fill certainly get more traffic.

If your web site is still newer I would go after some more small keywords at first and than go after the competitive keywords.

Go for real keywords after you fully develop your website.

One should pursue a good google ranking for an unspecific keyword relative with your site content, which requires more SEO skills