Ah calc, how I hate thee.
Like Kutulu said, the biggies are limits, derivatives, and integration. For the most part its memorizing rules and procedures to find these things, which isn't that difficult if you realize what they are measuring.
Limit: Essentially the number a curve approaches as its rate of change gets smaller and smaller.
Derivative: The slope of a tanget line to a curve at a particular point.
Integral: The area under a curve from point a to point b. Also the opposite of a derivative (i.e. if you diferentiate something and then integrate it, you get back what you started with, plus or minus a constant).
If you have any questions just ask here, for some reason its always easier to motivate myself to do other people's homework then my own.