Help from an Immigration Consultant
IRCC emphasizes that the use of representatives is not required nor does it ensure a successful application. But a Canada immigration consultant company helped me in 3 ways.
Access to Up-to-date or Note Readily Available Information
In my bio, I mentioned that I have an engineering degree and experience in the manufacturing industry. Also, I had experience teaching at a college. I used the latter in my application.
I submitted my application to the Federal Skilled Worker (FSW) Program in early 2010. At that time, the basis for my eligibility was November 29, 2008 Canada Gazette. The category College and Other Vocational Instructors was in the National Occupation Classification (NOC) for immediate processing.
The immigration consultant told me that changes to the FSW program are expected soon. These may include changes to the NOC list. So, I must submit my application as quickly as I can.
True enough, on June 26, 2010, several changes were introduced including a revised list of eligible occupations. Under these new rules, I would not have qualified.

Proper Documentation
Mistakes or omissions in documents may result in the return or refusal of the application. Due to the impending changes in the FSW program, proper documentation was extremely critical in my case.
The representative led me throughout the process to ensure correct and timely submissions. I was given guidance on what to do, how to do it, and when. For example, when to take the IELTS.
The immigration consultant prepared my documents. This included aligning my job description to the NOC. (This is similar to customizing a resume based on a specific job posting.) I only did a quick review of the documents once or twice.
Improve Chances of Success
During my time, the immigration pathways were much more limited. There were 3 possible options for me to go to Canada – as a student, provincial nominee, or skilled worker. Considering the cost, weather, and other factors, FSW was the most attractive.
However, my assessment score was only 2 points above the minimum requirement. I wanted to ensure that my application will be successful. The consultants then gave me advice on how to up my score. For instance, I enrolled in French lessons. As a result, I gained additional points under the second official language category.
The use of a representative is not required, nor does it ensure a successful application. But without an immigration consultant, I probably will not be in Canada.