Initially, our department advisor blocks everyone but majors from enrolling in J7A and J7B. We create, instead, a sizable waitlist. We then collect information cards at the beginning of the term and sort through these to determine who should be able to enroll. Thus there is no enrollment code to receive ahead of time to enter the class.
The decision on who to enroll is made primarily by our department advisor, but she and I do work jointly on the list. While I am able to make enrollment decisions, I concur with her approach and we basically work in tandem. Her priorities include enabling graduation for our majors as well as enhancing access for our majors and minors.
That being said, most of the time there is also room for others.
The best way to have the department advisor look favorably on your situation is to complete the card (available at the beginning of the term, sometimes directly from her, usually distributed by me) and, on that card, explain honestly, clearly and briefly why you need to take the class. If you feel you must talk with her, again, being brief, clear and polite will surely be the most effective approach. There is no advantage to completing a card before others, so you can wait until the first day of class to learn what to do, unless announced otherwise on the announcements section of my web site for the class (not bSpace) when available. In addition, flexibility regarding section enrollment is usually a plus.
The best way to have me look favorably on your situation is to attend the first session or two and, if possible, all sessions until enrollment decisions are made.
Do not entertain the concept of taking this class if other class commitments would require you to miss any sessions at all. For various reasons, including pop quizzes, it is truly difficult to do well in J7A or J7B without consistent attendance. It is designed to be that way.
Ranking on the waitlist is a minor or irrelevant detail.
Contacting me by email ahead of class is welcome but I will not review these emails when I consider enrollment. If you have a good reason to enroll in the class, it should be written on the information card. You can tell me as well; it might make a difference, but the enrollment card needs to duplicate that information.
Talking with me before or after class is similar to the email situation just mentioned above. I do like hearing from you but it is not likely I will remember our conversation since a lot is going on those first few days and, anyway, you have to repeat everything on the card and/or with the advisor. But how can saying hi hurt?
I cannot predict how likely it will be that you can enroll in the class. This is not because it is all that competitive but rather because available room size, student interest, department needs and such change so much from semester to semester that there is no real pattern that can be used for a reliable prediction.