Watch the Emoto-Trem online guitar lesson by Jennifer Batten from Rock Sauce For Lead Guitar
I am a huge advocate of using the tremolo bar and will go over every move I use it for. You can swoop into a note and glide out. You can get a more even vibrato than you can with finger vibrato. You can tap a floating bar to get a fluttering sound, and you can lift it up slightly to get more of an ethnic eastern sound. You can also play entire melodies in harmonics by playing a harmonic and moving to new notes with just the bar movements.