Read your syllabus early and figure out if the coursework is feasible. You may see that you are not going to be able to fit in to your schedule the four 10-page research papers required by that course during the fall semester.
Set a weekly study schedule for your online classes. I think it’s much easier to be proactive than reactive. If you have a weekly ritual, you’re more likely to stick to it and get your work done on time.
Do not wait until the last minute to review and begin working on an assignment. You may have questions about the assignment or rubric. You will then find yourself under immense pressure to complete last minute low-quality work.