Everyone gets a baitcaster "rats nest" eventually. If you get one...don't pull against the drag or against the tangled mess to get it undone. If you do, you will get some line off but pretty soon, you'll have a tight tangle of loops that might as well be a knot.
To get the line out "push" the (released) spool with your thumb to get as much line out as you can. Eventually, you should get to a point where the line is no longer loose around the spool. Click the reel into gear, pull against the drag one time and reel in all the line you pulled off. I spend less time cutting and changing line that way.
Here's a good video you could check out:
http://www.bonadon.com/101.htm
I'd also recommend staying away from the cheaper baitcasters. They'll make learning a lot more difficult.