For me personally I have a slow metabolism so keeping small is a bit of an effort. No one is in this thread to read about those bragging or complaining about a fast metabolism.
Some things I do when I start going up or want to maintain my weight...
1. Use MyFitnessPal and log every single calorie you eat. Do not lie, and measure everything out. Many find their predictions on serving sizes are way off. It helps you set up the amount you need to eat to gain maintain or lose weight based on your height weight age etc.
2. Workout at least 30 minutes a day 5 days a week if you have weight issues. I do 3 days 15 minutes of cardio, 15 of strength training. The other 2 I do 30 minutes of cardio and an ab regiment.
3. Don't do anything unrealistic to lose weight fast because you will gain it back. Everything in moderation works. You dont have to just eat veggies and fruit to lose or maintain weight
I have a bit of everything. If I really want something on a certain day I dont deprive myself of it. I have a small portion of it and adjust my other meals if I have to. Also don't eat past 7 imo.
4. Choose one day a week to have a cheat meal. Make it whatever you want within reason. For me fast food is a guilty pleasure so I will have about 1500 calories in a fast food meal. That day I usually eat at maintenance calories though so the rest of my day isnt eating very much. Do not have an entire cheat day to go crazy, and still count your calories.
5. Simply remember 3500 calories is one pound. Always be in a deficit and over time weight will come off.
6. Only weigh yourself once a week or you will go crazy every time a number goes slightly up. Weight loss is not always linear. You could lose 2 lbs a week 3 weeks in a row then all of a sudden gain 4 back then the following week you may lose 6. Never get discouraged. Also after a cheat meal or eating poorly you simply may weight more because you had a lot of sodium so you will have extra water weight being held on.
These are just some of the things I do/think about during the weight loss/maintenance process. I typically lose 2-4 lbs a week this way depending. I do have weeks I lose 0 even though Im in a big deficit but thats just how it goes. Its not hard to lose weight unless you have a real health issue. Most of the time people just cant get themselves to workout and are lazy, or need to evaluate how much theyre truly eating and what they are eating.