1) Always choose an Official Representative of the College or University because they have undergone rigorous vetting and compliance procedures to be accepted.
2) Always make sure they have a physical presence in Canada because its hard to regulate crooked agents overseas.
3) Always remember to ask questions and choose a course that suits YOU, not the agent.
4) Always ask them if they are RISIA or RCIC certified from Immigration Consultants Of Canada Regulatory Council (ICCRC).
5) You have a right to see their license with ICCRC and also with the Educational Institution they are representing.
Be Smart and Consult before making this momentous decision.