This one comes as no surprise and is used by serious athletes cutting weight to ordinary folks in desperate need of a snack. Simple, cheap and easy to bring anywhere. If you can't get this one right forget about the upcoming stuff.
Drinking water is a great idea regardless if you're dieting or not. Sparkling water offers the advantage of being much more filling than regular water. What about diet sodas? They can be a good choice for some people, but usually increase appetite which is the last thing you want when hunger is already in berserker mode.
Things are getting a little bit more serious now. You're about to open up the fridge and eat everything in sight. You don't care anymore, the hunger is killing you! What you need right now is discipline and some carrots. Or any other vegetable very low in calories and high in fiber for that matter. Carrots pack 5 grams of fiber per 100 grams and one pound of carrots is less than 200 calories. Look for the best combination of calorie count and fiber amount per serving when choosing vegetables for this purpose. Combine that with lots of sparkling water and you should be pretty stuffed. Instead of eating thousands of calories from your fridge, you got away with 200 calories. That's a win.
Similar to chewing gum you get a refreshing feeling by brushing your teeth or using mouthwash (the longer the better). I have yet to hear somebody say they left the dentist starving. Usually you leave the dentist office with your mouth being the equivalent to a pharmaceutical test lab. Plus that first piece of chocolate cake would taste awful when it mixes with your peppermint mouthwash flavour.
Not sexy at all, but it's crucial to make this a habit during weight loss phases. It's hard to concentrate when you're hungry. The best way to stop thinking about food is to get stuff done. Be active. Clean up your house, take the dog for a walk, take a shower - all these things are better than just sitting there and being tortured by ice cream daydreams. Get up immediately and do something.
With the popularity of flexible dieting/IIFYM meal prep has become sort of an exposing sign of not being in the cool kids club. Only idiot bodybuilders prep their meals ahead of time right? Fighting off hunger not only involves discipline, it also requires consistency. And consistency builds confidence and momentum. Being hungry is not that bad when you know you're just an hour away from eating the meal that's sitting right next to you in your backpack. Being prepared feels good. Being prepared demonstrates that you are in control. If meal prep is absolutely impossible for you, you could just plan your meals for the day with the tracking app of your choice. Do not underestimate this strategy. Knowing what's about to come gives us a feeling of security. It is no different with food.
This is entirely anecdotal, but drinking BCAAs (powder, not capsules) in water does a fantastic job of killing off hunger. I'm aware that research in favor of BCAAs as an anabolic aid are a rarity, and that's not why I recommend them. I solely recommend them for reducing cravings and hunger signals. If you're using 10 grams of BCAAs with (again) lots sparkling water, you can stay pretty sane for hours without food. And you are only looking at 40 calories total.
There can only be one king and he reigns supreme over the kingdom of hunger control. While training requires the greatest effort out of all 8 approaches it offers the most benefit as well. You can effectively suppress hunger for hours with a single training session. Rest days are incredibly tough during a diet because of this. Instead of being in the gym you're now hungry for an additional 2-3 hours sitting at your desk. A cardio session instead of weight training can help here, even though it's gonna be shorter than weight training in most cases.
I highly suggest you try all 8 things on this list and combine them as you see fit. If you want to go all in and really have to bring calories down significantly, all 8 strategies should be employed. Take pride in being disciplined and consistent. Be comfortable being hungry and know that hunger is coming. And when things start to fall apart, don't reach for the cookies. The carrots are right next to them.