We may with advantage at times forget what we know.

Knowing how something is done makes you fast and also makes you blind, because the known method arrives before the question does. Experts miss simple solutions that beginners find, not through carelessness but because the path is already worn. Setting your knowledge aside for an hour is a way of getting your eyes back.

With a problem you have handled many times, try describing it to somebody outside the field and listen to what they suggest. Or ask what you would do if you had never seen this before and had to work it out. Take the old method back afterwards if it still wins.