I adjusted my valves today (only the second time). Went fine, truck sounds good. To avoid mistakes, and to speed up the process and to keep the engine hot, I used clothespins to mark the Intake and Exhaust valves. Just clipped them onto the rocker arm (marked with either an I or an E). When I got a valve adjusted, I pulled off the clothes pin. As long as you double check I vs E when you put the pins on the first time, then I was able to move through the valves pretty quickly without worry that I got one wrong.