Systematically ask challenging questions to jolt you from your frame of comfort. Look at the problem with tools such as ‣, red teams or pre-mortem analysis which further challenge the frame you may be looking from by introducing diversity of thought. A good list on the 10x curiosity blog or something like Bria Eno’s Oblique Strategy cards which introduce shocks and doses of randomness into a situation.
Promoting diversity of thought is one of the tactics of a High-reliability organisation.
One of the principles of Connectivism learning theory is that "learning and knowledge rest in the diversity of opinions".
Part of Diversity.