I would suggest that you visit sewing.about.com and read some of the information pages there. Or buy/borrow from the library a basic sewing machine instruction book. There are several feet that make certain sewing tasks easier such as the blind heming foot, rolled hemming foot and zipper foot. But for much of your straight seaming, you will just use the main sewing foot or the plastic see through foot. A teflon coated foot is great for knits as it slides a bit easier. And a roller foot with two rollers front and back is for sewing vinyl or leather which doesn't slide like fabric.
Also, if you go to www.sewingpartsonline.com
you can see images of various pressure feet with their names and this may help you to identify the different feet.
There are some specialised feet such as a cording foot to assist you to sew over cording, never used it! Or the pin tucking foot which helps you to space the rows of pin tucking.
If you learn the basics of dressmaking then you'll learn to use those special feet.
Any my all time favourite is the ruffler, it looks like a tool of torture but works beautifully if you want to put a frill around something big like a bed dust cover.