"In art, truth and reality begin when one no longer understands what one is doing or what one knows, and when there remains an energy that is all the stronger for being constrained, controlled and compressed."— Henri Matisse
Or in other words go fast! Get out a sketch pad and start drawing sweaters. Do as may as you can as fast as you can. Don't allow your logical mind to stop and say things like that won't work because..... Just generate as many ideas as you can with out stopping. The theory behind this is that from the brain's perspective extreme speed can unlock creativity. When you force yourself to come up with ideas under time constraints, you're forced to rely on the more intuitive, subconscious parts of your brain. The time pressure can help suppress the logical, rational and critical parts of your brain. It helps you access your subconscious creativity in your right brain and limits your ability for the conscious thought of left brain.
If you get stuck trying this try limiting yourself even more. Try focusing on one technique only and generating ideas around that technique. If you still need prompting try it this way. Set your kitchen timer for ten minutes and sketch fifteen ideas for Fair Isle projects.
Get ready! Get set! Go!