You can calculate the consumed power of the motor by multiplying current and voltage. One of the most difficult tasks is the speed measurement. The electronic counter I used in my project is a complicated device and can be recommended to experienced users only. There are some other suggestions I received from my customers that may simplify the speed measurement. Mark Seale suggested to use a strobe light to determine rpm.
Many strobe lights have active counters showing the flash rate.
Brad Higgins used a bicycle counter to calculate the speed. Several other users attached a string with a small weight and measured with stop watch the time needed to lift the weight the certain distance. Measure and compare different electrical parameters as described earlier. If you are building a reed switch motor you may add a speed control unit to it. You may design a device to measure the speed in rpm or find any other way to do it.