Below is a screenshot of the text file I use. Yep, old school Notepad .txt files. I find Notepad just an easy no nonsense program that all computers can open.
It's taken a while to evolve to what it is now. But now at a glance I can see all the exercises, and different weight/reps/sets options. After each workout I'll see if I can go heavier in any of the lifts, or even drop the weight if my form is suffering. I'll alternate the reps and sets every 4 weeks, so the first week I'll look at my notes before I leave work and head to the gym. Then after a few weeks in I'll know what I'm doing.
I also have a similar text file for diet.