Its good occasionally to just play randomly within limitations and put yourself to the test. Like starting a drawing from a scribble or drawing without looking at the paper. All these things will break you out of your 'auto-pilot' response to any drawing problem. Relying on your habitual drawing ticks can make for really boring solutions. That's why playfulness and doodling are so important. When people say how do get your ideas, the answer is simple: you don't think - and then they come.
Here's some instant responses to fingerprint shapes - thinking time 2 seconds, drawing time 30 seconds at most.