Taking the stairs instead of elevator when I'm at walk ups
Seriously tho just get in on some major compound exercises few sessions a week is good enough. Squats, bench press, deadlifts, pull ups, standing military press, etc. Then add on more targeted lifts of you have time and energy but at least hit those big lifts.
You'll never out work your diet tho. You can be in shape as in very strong but look flabby especially since it's so easy to eat too much calories while in hk. So much food out there that are calorie dense and full of carbs and fat.