Go to IRC's site, buy the study guides and study - then take tests. Simple stuff. I read their study guides for mechanical, plumbing, electrical and building. Bought a Code Book. Signed up for tests (1 every 2 weeks - took them - passed) and got certified in all 4. The only test that gave me any problem was the electric. Was a real shock to find out I passed. Lot of questions about things that we don't regularly see or do, such as how many wires can be in a square box that is xx" by xx".