Watch the Emoto-Trem online guitar lesson by Jennifer Batten from Rock Sauce For Lead Guitar
The tremolo bar is a tool to enhance expression. It got a bad rap around the time grunge music entered the scene, mostly because people were using it in a very limited way, and mainly doing extreme dives. But there's so much more expression you can get out of it. Don't worry too much about how it sounds at first. Just get used to how it manipulates a note or chord, and learn how far to push or pull to get a sound you like. Your brain will automatically log every time you do something that is pleasing to your ear, as well as log the opposite. Eventually you'll get it so it just sounds good to you.