A few thoughts on how not to sabotage your diet when you're trying to lose fat -
Not weighing your food - I have no idea why people are so fucking lazy they avoid doing this. Especially for the first few weeks until you can sort of "eyeball" your portions. An extra ounce of nuts every other meal could mean the difference in an extra 1000 calories for the week. For your calorie dense foods like red meat, nuts, and oils, it is imperative that you be precise in measuring. If you're too lazy to measure your food, then you're probably not too serious about your fat loss either.
Weekend binging - I may do a long article about this in the future but basically, your entire week of adhering to your diet can be undone over the course of the weekend if you're still not being strict. The weekends make it more difficult for some because of going out, family gatherings, attending social functions, etc. This doesn't mean you can't "live", and enjoy some of those foods, but a lot of people have no idea of portion control in those situations. What's the point in dieting all week if you destroy all of your efforts every weekend?
The reward system/cheat meals - I've harped about this before, but it's a big one. I have especially seen this in females. The whole "I did my cardio all week and didn't cheat so I deserve to treat myself." That's fine. But treat yourself within REASON. I think the cheat meal has become the most overrated piece of shit in dieting advice. The fact is, you don't need one. If you need one for a mental break then understand that turning a cheat MEAL into a cheat DAY may have the same effect as the weekend binge. Also, I have no idea why someone needs a cheat every week. You can't stay on a diet longer than a week without breaking from it? From my own personal experience, the longer I went without having a cheat meal, the faster I lost fat. When I kept it in on a weekly basis, progress was much slower. I would suggest setting a goal like "lose X amount of pounds before I have a cheat meal." That or a longer timeline, like one cheat every 10 to 14 days. You don't need one every 5 days for damn sure.
Not counting all your macros - You'd be surprised at how many calories you sneak in with shit you aren't counting. Like bar-b-q sauce or alcohol. I told a client a few weeks ago "whatever food or drink goes into your mouth has to be accounted for." That means if you're slathering a sauce all over your chicken or steak, check the label. A lack of progress could be because you're using a lot of sauces and over the course of the week these are adding more calories than you are accounting for. Same for drinking alcohol. It counts.
Not eating enough - The main reason I am listing this one is not because of what you think. It's more about cravings and binging. Too few calories can be self sabotaging because it can cause significant binge eating when the body signals to you that you BETTER FUCKING EAT. I think anyone that has dieting hard for long enough has had that hunger urge so strong that it felt almost impossible not to cheat and eat 14 peanut butter and jelly sandwiches. If you are dieting, you will probably be hungry at times. But if your calories are too low the cravings could get too strong to be ignored. Remember that fat loss and body recomp shouldn't be something you're planning to do in 2-4 weeks. Make sure you have an adequate time frame to allow it to happen gradually and systematically.
Depending too much on cardio - One hour of walking at 3.5 MPH for a 200 pounder only burns about 400 calories. That's one piece of cheesecake. So one piece of cheesecake can undo an entire hour of walking at a brisk pace. The body is made to be energy efficient. It doesn't expend a lot of calories to perform, so calorie dense foods can undo your movement efforts very easily. It's easier to NOT EAT the 400 calories, than to exercise for an hour to get that deficit. Cardio or various forms is a good idea as a SUPPLEMENT to aid in fat loss, however it should not be something you're heavily dependant on.
One thing I tell people is that if you plan on dieting or hire a diet coach, measure your food, eat ONLY what is listed, and then make adjustments as you go. If you don't do it EXACTLY as prescribed then how will you know what you really need to change if it's not working?