For example: I'm following an online program. Each day offers new exercises, machines, etc. Do you write down what exercises you are doing at the gym that day? Do you take your phone and use it while you are there?
I keep a training journal in a Word document. I've used the same format since 1996 and have all of them going back to day 1. I also track mileage and other stats using my Garmin and Garmin Connect these days (for about a year).
My format looks something like: Date: Ride: (Road/MTB) Distance: XX miles Speed: XX mph Time: hours/minutes Description: A description if I did anything specific like intervals. How I felt, how my HR was, etc.
I don't track my workouts at all. Each year I say I'm going to and have good intentions but then I don't. I do plot out my long run schedule in my daily planner though.