"Losing fat means eating less" is one of the most common misconceptions out there — go hungry for a few days and you're likely to swing into revenge eating, which just makes the weight bounce right back. What actually works is pairing your foods wisely, so you can eat until you're satisfied while still keeping your total calories in check.
Everyone's baseline calorie burn is different, but there's a general range to work from. Rather than memorizing numbers, just look up the calorie counts of a few foods you eat regularly, so you get a rough sense of "about how many calories is this meal" — far more useful than guessing based on what the scale says.
Take staple carbs, for example — rice and sweet potato have noticeably different calorie counts even though they fill you up the same way. Same goes for protein sources — chicken breast versus pork belly is a world apart. Check a food calorie chart and swap in options with similar total calories but that are more filling and more nutritious — you can cut your overall intake without ever feeling starved.
You can't weigh your food at a restaurant, but you can break it down roughly by ingredients — a serving of fried rice is roughly equivalent to so much rice plus so much oil. Look it up and get a ballpark sense; you don't need to stress over every single bite, just a rough idea is enough to work with.
The food calorie table currently holds 1,706 entries. I picked three from it: cooked rice at 116 kcal, raw chicken breast at 133 kcal and raw broccoli at 34 kcal, where the column header says kcal per 100 g. For a plate of 150 g rice, 120 g chicken breast and 200 g broccoli: rice is 116 x 1.5 = 174 kcal, chicken is 133 x 1.2 = 159.6 kcal and broccoli is 34 x 2 = 68 kcal, for a total of about 401.6 kcal, not counting cooking oil. Two cautions. First, the chicken figure is for raw weight, and weight changes when cooked, so always weigh in the same state as the table row. Second, not every row is per 100 g: the row for one whole egg (about 50 g) lists 78 kcal for the single egg, so adding one egg brings the plate to about 479.6 kcal, and you must not multiply that row by grams. As for the comparison in this post, raw pork belly is listed at 395 kcal per 100 g, so 120 g would be 474 kcal, about three times the chicken.
Losing fat is a long game. Understanding roughly what you're eating and how many calories it holds will carry you a lot further than obsessing over the number on the scale.