When you are on the runway and have completed your pre-takeoff checks, be sure that you have selected takeoff power (full), and confirm that the engine is producing takeoff power by checking the RPMs indicated during the initial roll.

The reason for the visual inspection of the RPMs is that it is an important means of detecting an engine problem.  If there is an exhaust system blockage or a cylinder malfunction, you might not detect the problem in the run-up, nor will it be apparent by such things as takeoff sound or acceleration.  Engine problems should, however, be indicated by lower than normal RPM that indicates that the aircraft engine is unable to develop its full-rated horsepower.

Therefore, get to know what power is normally indicated by the RPM gauge during the initial acceleration for takeoff after full power is selected.  In the cockpit, say “maximum power” out loud when the throttle is fully applied, and then say “confirmed” when the RPM is verified.  This is professional, and it makes safety-sense.