Error can be managed at several levels.
Good system design should provide feedback for any action and information resulting from the action must be clearly displayed. Crew members must look for this information and understand it - situation awareness. E.g. an auto flight mode control panel should have annunciation at the point of operation and at the point of use i.e HDG is displayed next to the control knob and on the EFIS.
Well thought-out procedures, whether written or memorised, aid error detection. E.g. during takeoff instead of calling ‘power set’ a better procedure is to state the value of the power i.e. ”Power Set 91.4%” This reinforces the check of the power required and enables the non monitoring pilot to detect any gross error. It also builds experience of what power settings are normal for a range of situations and focuses mental attention on important parameters, thus avoiding a ‘habit’ call without actually checking the value.
Appropriate personal behaviours are essential, particularly in not rushing when taking action. Good knowledge of systems and aircraft performance will enable you to anticipate situations. Training for abnormal operation should provide experience of unusual situations, but remember there will always be a surprise factor and high stress levels; controlling stress also controls any tendency to rush. Think about the process of problem solving, not necessarily about the end solution, but the questions to ask in order to reach a solution. If you ask the right question, the solution is then obvious.
Be part of a team, they are the primary defence against your error.
Remember that everyone in a crew is equal, they all make errors; only the commander has the authority to make big errors.