Welcome to POTN...
You've got a very capable light gathering device in the 50D but it's not a magic box. The magic is between your ears.
Instead of worrying about what you aren't getting right now, take the time to do some studying (your camera manual, other books, DVDs and especially POTN .. world's greatest on-line photo seminar!) and imagine what's possible!
Above all else: Shoot. Shoot Again. Shoot some more. Photons are free and 1s an 0s are cheap so use 'em!