Short sweet and to the point.
Be aware of the deadlines to drop a class without it being on your permanent academic records, convert a class to pass/fail, withdraw from a course.
Hopefully these deadlines fall after the first exam or major assignment is graded. At my school, the "course-drop" period and the "pass/fail" deadline fell after the first exam leaving me and my fellow students with the only option to stick it out and hope for the best or withdraw from the course with a permanent "W" on our academic record.
I didn't know there was a "pass/fail" option until my third year of school. I used it the same semester I learned of it. I was a Biology major and was taking three upper level science courses and one elective course to complete a general requirement. Because of my experiences in my freshman and sophomore year, I knew that no matter how easy the elective is, I would not be able to dedicate enough time to it so I made it pass/fail. This decision worked wonders for that semester.
A friend of mine took organic chemistry three times. First she dropped the course, then she withdrew from the course, and then she completed the course. She was pre-med and through all of that, she still made it into medical school.
Learn these deadlines, embrace these deadlines, and realize that choosing any of the three options is not the end of the world.