If you are doing it for the first time get your camera and take loads of pics before you start. Make notes of which wire goes where and label them. Have a small box to put nuts and bolts in. Work on a drop sheet to catch the bits you will drop. If you are taking brushes out then be very careful with the internal wires- they do not like being bent around too much. If you are taking pumps apart then watch for the pressure relief springs and poppets.
If you do not have them get some decent spanners, adjustables are usually too clumsy. The spanners with a ratchet head are handy, save taking the spanner off every 1/6 turn. I mostly use 8, 10, 11, 12 mms.
Take your time and you will find its not difficult.