Be topless as much as humanly possible.

More effective than ‘calorie counting’ or other nonsensical ideas.

The general idea:

If you spend as much time during the day topless, you get a better sense of your body composition (your muscle mass, your body fat percentage, etc).

If you don’t like the way you look, or if you feel you got too much body fat, or not enough muscle, it gives you the motivation to be insanely strict with yourself (fast during the day, and cut out all starches, carbs, sugars, etc).