What a beautiful little girl!
...and she sound's perfectly normal.
It's not so much that you're doing anything wrong...rewarding good behavior, time out's when she's bad or taking away a toy, these are all OK...
At four, she's getting old enough to start realizing that actions have consequenses, so as much as you can, tailor the discpline to the behavior. If she won't put her toys, take the toys away for a long period of time, this sort of thing.
But the main thing to keep in mind is that this isn't so much that you're on the wrong track with her discipline...just that she is testing the limits. Testing the limits is very aggravating to us parents, but it's very important that we stick to our guns and consistantly follow through with discipline. This is how our children learn that we mean what we say and they are going to face consequenses for bad behavior as well as be rewarded for good.
Hang in there! This is a very key "battle"...if you remain consistant and build a foundation in which she learns that her actions will always bring about consequenses...you'll save her (and you) a lot of headaches and heartaches in the future!