2. Identify a subset and research what they do and the jobs available (don't attend a career fair and ask companies what they do, your resume will be ignored. Show that you at least have a cursory understanding of what they do and ask intelligent questions)
3. Attend the career fair with a number of resumes at the ready
4. Ask recruiters how to apply for their internship if they are offering them
5. Get the recruiter's business card
6. Apply to the internship (most are online today)
7. Follow up with the recruiter with a thank you email
Repeat as often as necessary.
As mentioned above by a few people, sometimes the best plan you can do to get into an Accounting Internship would be to do you're research. I would suggest what a few people ahead of me have; Join your College's Accounting Club, Go to your College/University career fairs, see if there are any upcoming meet and greets with prospective employer's you would like to work for. As long as you have an idea of what area of Accounting you would like to work in, be it Corporate Tax, Small Business, Audit or even MnA. Look into the firm's internship programs and speak with your school counselor to see what additional opportunities you can be missing out on that your school can provide.
Personally, I got my internship with PwC by going to a Meet the Firms event at my college and filling out an online application. A different internship I did I got through my college's internship program's website (filled out the application there). Most companies and most colleges would have similar online applications I believe.
I am not sure if it is the same way in Canada, but I'd think it would be a similar process.
Casey recommends the following next steps: