There are no magic diets, magic workouts, magic supplements (unless you are using "special sports supplements" ie anabolics).
There are a couple rules that apply:
1) Eat protein, 0.6 - 1 gram per lb of bodyweight, depending on age (you need more as you age), activity level (harder training, more protein) and whether you are trying to gain mass or lose it. Eating more than a gram per lb of lean BW doesn't show any benefits based on a massive body of research, unless you are in a huge caloric deficit and trying to maintain LBM, think competitive bodybuilders.
2) Supplements (except creatine, caffeine and protein supplements), basically don't work. Those that work have a minimal effect on performance.
3) Sleep, for the love of God. Lack of good sleep crushes your hormones panels and is generally like a nuclear bomb to your physical and mental health. Turn off the phone/TV and sleep.
4) Alcohol, for the most part, just don't drink it. It wrecks your sleep, is terrible for your heart, liver, and brain. It also makes you want to eat garbage and really affects how you metabolize fat while drinking.
Moderation is the key to long term success. Fad diets (carnivore, vegan, etc) rarely work long term and most, if not all, have negative health consequences.
Basically, it boils down to discipline. Most people know what to do, they just don't have the discipline or mental strength to do it.