I'm assuming that you are asking about printing, and have safelight illumination.

A largish battery operated clock with a sweep second hand works well once you get to the point where you know the timings off by heart. Just make a mental note of what the time will need to be at the end of each step in the process when you commence that step.

Oh, and make sure that the sweep second hand itself isn't red or orange - otherwise it will be really hard to see under safelight.