1) set a schedule and a time for exercise
2) make a checklist so you can tick off when you have completed an exercise.
3) you can set an aim on how many calories you want to burn
4) write notes on how often you work/worked out and for how long (on each exercise)
5) change up your routine so that your body doesn't get too used to the same movements
6) plan rests (usually 30 second breaks between each exercise)
7) also note your diet. this should be healthy and balanced to maintain proportion with amount of exercise.
Hope these tips help with your journal :)