Something else to consider, and it's an exercise I'll still do from time to time myself, is a whole campaign. Create a fake company (Continental Lint, for example) and create a business card, a letterhead, an envelope a full page print ad and, just to make your head explode, a billboard. Doing billboards taught me a lot about print design because you've got to create something that can be easily read and have an impact viewing it for 8 to 10 seconds (or less) while zipping down the highway at 70 mph. It's sort of like doing banner ads for web sites, only larger...and they aren't animated, but it's the same basic concept. Copywriting ain't easy either. If you're lucky, you won't have to do it much. If you're not lucky, practice, practice, practice....