Sam offers some good advice. With specific class assignments one has to do things.
Another nice option with today's digitals is that one can learn a ton just sitting in his Lazy Boy, reading the instruction manual and actually playing with all the settings. Dink around with ISO's, shutter speeds, white balances, exposure bias, and apertures with just the house lights. Do increments of only one aspect at a time. See what it takes to shoot into dark/light corners, capture motion on the TV screen, or expand/contract depth of field. I'm one that learns best by doing, and the upside is it can all be viewed and deleted at essentially no cost.
Also, when one downloads and reviews his serious efforts, look at all of that metadata info that accompanies each shot. Very informative, especially for those shots that we hoped were great but we screwed up somewhere.
Go forth and play,
