Clear thinking is the road to inventive ideas.

"I believe the only ideal a designer should work to is complete clarity of expression. Not only clarity of words, or clarity of picture, but 'idea' clarity. Whatever is to be expressed must be thoroughly understood before it can be successfully communicated." - Visual Expression by Ashley Havenden

Although we are taught this from the beginning of our design backgrounds, it can never be said enough because realistically, there is a shitload of design out there that has no clear meanings behind it. And we all fall into the trap of doing it again at some point if we aren't careful. Don't just design for design's sake. Design it to carry a meaning, an idea, a clear message to the viewer. If it doesn't, you failed.

You cannot let the viewer be distracted by your type treatment or the way it's layed out. The average viewer should not really even notice these things except to get the information easily. They can appreciate that it's well designed but if you are trying to get a message across, and most of the time you are as a designer, the actual "design" should not be the main focus of the piece. The information should be. I think as designers we sometimes forget this and get wrapped up in trying to get "our" part into the design.