Complete a beginning of the semester evaluation for the course. The evaluation will typically ask you general questions like whether or not you have ever taken an online course, or what your expectations from online courses are.
Go to the course site a week before the class begins and begin to familiarize yourself with the tools and resources used by the instructor. If there is an introductory video to either the course or the site, watch it.
Go to chat rooms and chat with other students belonging to the class, or send them an e-mail introducing yourself and asking them a few basic questions about their online learning experiences. Generally, at least one or two people in the class will have had the instructor before, so they may be able to tell you a little bit about his or her teaching style, if you are unfamiliar with it.
Report any technological issues to the instructor as you soon as you notice them. This will make your online learning experience a lot smoother, and you will not be e-mailing the instructor the day an assignment is due explaining that you can't access the necessary material because of an Internet glitch.
Complete an evaluation for the course at the end of the semester. These evaluations are usually anonymous, so be as honest and as thorough as possible. Avoid criticizing things that were not the instructor's fault, like if the course site was temporarily down or wouldn't load for a few hours one day.
Let the instructor know how you felt about the course and how you feel about online learning in general. Your feedback may lead to positive changes in the way the course is constructed or taught the next semester.