You don't. You don't even count calories, as those vary widely compared to the count on the package/menu.
It seems it comes down to this: Eat a variety off foods. Get some protein sometimes, eat fruits and veg. Try to get whole grains in there. Watch the added and refined sugar, regardless of source, but there is no need to avoid it entirely. Make sure to eat some fat and dairy. Heck, even high activity isn't necessary if you make the right life adjustments (like walking most places) or have the right sort of job. Cook your own food, and develop a few flexible meals that are easy and nutritious. Stir fries and the like come to mind.
The real trick is the personalisation. For myself, I'm hungrier in the evening so I eat lightly during the day. I skip breakfast (I'm not hungry). I eat fish but not other meats, but this is mostly due to the lack of a gallbladder. I also had to learn to be more comfortable with hunger. I did this with a combination of delaying snacks (it is easy to tell yourself to wait a short time) and working on portion sizes. The last one was simple: I'd eat a portion, and be done. I always knew if I was hungry in an hour or two, I could get a healthy snack. The snack rarely equals the food I'd have eaten if I got more on the plate, so it works.
And just to be fair: At one time, I weight over 200 pounds. I'm a 5'6" woman. I now am fully in a healthy weight and trend towards thin. I'm don't know my weight, but i'm about a size 6(US) and have kept the weight off for years with only minor fluctuations.
Edit: I should mention that I didn't keep good records, just observed my general diet and made improvements and adjustments.
