Okay, I recognize that there is a bit of a contradiction here—generating useful ideas usually requires a lot of experimentation, which isn't a very structured activity. This is true; however, without some level of control the process becomes time-consuming and chaotic—deadlines are missed and quality suffers. Dividing a workflow into several phases, each with a specific goal, let's you be creative and efficient at the same time.
Clearly define what you hope to accomplish. Most class assignments and commercial work have specific problems that need solving. Be sure you understand the problem before starting anything else. You need to know where you're going if you're ever going to get there.
Generate lots of different ideas. Don't settle for the first thing that comes to mind—look for the unexpected. At this stage the ideas should be wildly different, not just variations on a single theme (a common student problem). Choose three or four of your best ideas and refine them. As you work, compare your ideas to the goal you set in step one. Abandon anything that strays from it.Turn your idea into a finished product. If you're creating an image, let your idea inform your design decisions—every visual element should strengthen your concept.
Be sure you understand the problem before you start working on the solution. I often see students working really hard on a project, creating something wonderful, only to find it's not the right solution to the assignment. Excellent work from a technical and aesthetic standpoint, but a failure nonetheless.
Most classic ideation techniques, like brainstorming, rely on manipulating words or building lists. I have effectively use the following approaches in my work:
Ideas don't come from living in a vacuum. We need to experience life in order to build a collection of material for future use. In particular, it's important to immerse ourselves in other people's work, both good and bad. Good work reveals qualities we can incorporate into our own work; bad work encourages us to consider better ways of doing things.
Clear your mind, close your eyes, and visualize. Often times our best concepts seem to come out of nowhere. Meditation lets us tap into our subconscious to find possibilities that may otherwise escape our notice.
Dreams, if you are lucky enough to remember them, are another good source of unexpected ideas. Ideas inspired by dreams are often intense and offbeat—characteristics that are sure to command attention. Just be sure to jot down the high points of your dream immediately after waking to prevent you from forgetting them later.