I would say the best way to catch things is check and double check. Even if you do a scan just before critical phases of flight, before take off, top of cruise etc you can pick up on things not being set correctly very quickly.
I always before entering the runway check flaps, brakes, trim, spoilers.... as someone else said, this one action can save lives.
The problem comes when you are starting to feel fatigued after lots of flying, staying vigilant is difficult
