Probably needless to say, but I'll say it anyway. Ground the aircraft, ground all the tools you are using to the highest extent possible (go to an IT shop - they have special anti-static mats, clips and wristband that are all connected, and are used when working with sensitive electronic components), keep fire extinguishers to hand, don't wear flammable clothing or clothing that may generate static electricity. And if you are going to be hanging over an open fuel filler neck for a while, consider using appropriate breathing protection.