Let us begin :)
The first thing to know about either low carb or keto is that you need to start with two things from day one, or else your diet is doomed to fail. You need a good multivitamin, and you need fiber- lots of fiber. These two things are stated in most Atkins books, but are often overlooked or not done right (I made this mistake, and so has every other low carber I know haha). You need a multivitamin that received great reviews in terms of absorption, has all vitamins and minerals in quantities recommended by FDA or only a bit more, and also has energy boosters and herbs in it. As for fiber- let's face it- almost no one is getting enough. The newest numbers, which I agree with from personal experience, are above 20g per day for adult men and women alike. Now, even when you eat pastries, fruits and veggies on a regular diet, add all those up and you'll notice 20-25 grams per day is not easy to achieve. What's more, consume too much in one sitting without drinking enough water and you'll get unpleasant side-effects for sure. Best way to go about this is to add up fiber from the veggies you choose to eat on your low carb or keto diet, and supplement the rest with something like psyllium husk. Take it in the morning and evening, followed by an extra glass of water each time and you'll be ok. This is absolutely crucial because otherwise you won't feel full from fat and protein alone, you'll overdo it with the calories, and you'll get horribly constipated over time, making you abandon the diet completely.
Speaking of calories, yes you should run a calorie deficit after the first week of getting into the diet. There is no effective diet where you can eat like it's your last day and still lose weight. Also, and this is key, the lighter you get, the less calories you should consume because your daily caloric needs go down with your weight. Once you're much lighter and simply decreasing calories puts you in the starvation range, keep the calories up but increase the amount of calories burned daily through activity. Getting a Fitbit, Apple Watch or a cheaper but accurate competitor product comes in very handy here because you don't want to overdo it with too much activity either, which would put you in starvation mode and force you to break your diet in a flurry of junk food.
Speaking of junk food, low carb and keto diets limit away far more foods than many other diets. Fruits, some veggies, patries, pasta and more have too many carbs and are therefore excluded. Still, after a month or two you need your bread and desserts back or else you won't go the distance. Believe it or not, there are no-nonsense low-carb breads. You may want to check if anyone in your city bakes them, find a family member or friend who can bake some for you, or try to do it yourself. They are easier to make than regular breads because you don't wait for the dough to rise and so on. Also, the ones I tried so far do not mess with my blood sugar, nor do they kick up any cravings. Finally, they are typically rich in fiber so you get to drink less of it. As for desserts, there are creams, mousse, cakes and more that are low carb and utterly delicious. Some dessert shops make them (for example, Toronto has a few spots), while others you can easily make by yourself. Either way, when it comes to both watch out for a few things. One, both low-carb bread and desserts are more expensive than their regular versions because they are made in smaller scale and utilize lower carb yet more nutritious and consequently more expensive ingredients. There is no way around it, it's a fact of life. Second, while bread is reasonable in calories, the desserts pack a wallop and you have to stop seeing them as things to eat lots of and after actual meals. You either make them one of your meals every other day, or portion them out carefully and decrease your main meal if you're going to have one of these desserts right after. If you fail to follow this, your weight loss will stall and there will be no more weight loss until you make the necessary corrections.
Finally, to keep things going for months, make sure you take up meal prep at least in terms of meat, and use lots of different spices- try new ones for the fun of it and to keep variety alive. I like to prepare lots of boneless skinless chicken, rub different spices and oil on it, then leave some in the fridge and the rest packed in the freezer- every freezer bag has enough chicken for a single meal (e.g. 3 boneless skinless thighs). That way, you just pop it in the oven or on the grill, add some veggies or salad, and you're ready to eat fast! Remember, most of us are too busy to cook every day if we have to cook from scratch. That's why it's a good idea to do these kinds of shortcuts so you don't end up ordering Chinese food on a weak, emotional hungry evening and undo at least a week of dieting. Know yourself, and prepare for it :)
There you have it, gentlemen and ladies- a few advanced tips delivered in a stricter than usual tone to highlight their importance. Your turn ;)