Use toothbrush/ qtips to clean hard to reach places
Remove bolt and use microfiber to wipe and clean all lube and oil off all moving parts...bolt, rammer, springs
Run a clean squeegee through breach and barrel
Detach bolt system and lube all o-rings and moving parts with correct lube/oil
Remove parts needed to get to your eyes/ detents and make sure they are as clean as new
If your marker is electronic make sure your battery is new
Check between & clean frame/ body, behind grips, behind or around the trigger
Your gun should now be inspected and cleaned make sure all wires and or parts are connected and put back in there correct spots including all o-rings and seals.
Put gun back together, slide the bolt in, connect to your tank make sure there are no leaks and if not your good to go.