The worst enemy to creativity is your current knowledge. You think you know and thus you keep trying and coming up with ideas based on what you know. Let go of what you know and free your mind to discover new and better ways to do something.
"Imagination is more important than knowledge" – Albert Einstein
In order to become creative, you need problems. Yes, you heard me right. You need to generate problems you never knew you had. Turn questions to yourself into defined problems because problems are a fundamental part of the creative thinking process. It's nearly impossible to be creative without problems.
In order to be creative you need to NOT know what you know. Weird? Yes. Difficult? Yes. Valuable? Extremely.
Remember - It's pretty much impossible to be creative without a real problem. If there's no real problem but something you have an answer for, but need a better solution than the current one, then you need to define a new real problem to activate your creativity.
Knowledge is the killer
The more you know the less you have to imagine. And the less you imagine, the more usual your thoughts become. Most people don't come up with great ideas because they come up with good ideas (the traditional), then stop.