Wash lemon under cold water and use your vegetable wash or soap. Some people actually have a brush that they use also.
Hold the plane in one hand firmly and take the lemon and run it down the microplane. Lift it back up and repeat. Turn the lemon as you go so you continue to just get the peel.
Alternative: Box Grater
Hold the grater firm in its location and run the lemon up and down on the rasp of the grater. This cutter goes both ways.As you remove the peel turn the lemon. Focus on removing just the yellow part of the peel.
Tip: Make sure you are only getting the lemon part of the peel. The white part of the peel or the "pith" is very bitter and you don't want it.