Do a survey of a course before you take it, such as reading a general history on a topic or several Wikipedia articles on the topic. This might include studying one of the many online university courses or other Top 20 resources such as Khan Academy. For Calculus, watch the 15 videos above on this Top 20 calculus page before taking the course to understand some of the basics concepts and get off to good start. All of the videos can be watched in less than 10 hours, or one hour a day for 10 days. See also: How to Study Mathematics from Paul’s Math Notes.
Get off to a good start also by reading part of the textbook or the reading list before starting the course.