In most cases, obtaining a work permit for Canada isn’t easy because employers must firstly prove that there are no qualified Canadians that are willing, ready, and able to work the proposed position.
The rigorous qualifying process is referred to as a labour market impact assessment or LMIA. The LMIA is part of a larger exercise whereby employers must advertise in several sources, fill out an application, submit corresponding fees, and allow service Canada to decide whether hiring foreign workers is justified.
Obviously, the more a job is considered attractive, the more likely it is that Canadians will want to apply. Strategically speaking, someone wanting to obtain a Canadian contract should look for sectors where there are a lot of jobs and where job vacancy rates and turnovers are high.
It is important to note that although some jobs do not need to be supported by an LMIA, these are part of the exception rather than the rule. To find out the exemptions to LMIA which offer open work permits not restricted to a single employer, refer to the Government of Canada web site.
To applicants whom succeed in obtaining at least one year work experiences as a temporary foreign worker, for the same employer; your chances of obtaining permanent residency will improve exponentially.
Finally, it is important to understand that coming to Canada by way of work is considered part of the economic immigration stream. As such, work can only lead to permanent residency if there is a proven language ability for either French or English.
Improving your english, or studying in Canada in a program that offers post graduate work permits, are often the most promising options to find a job or achieve eventual residency through economic classes.