Get on Cronometer.com, invest in some measuring cups or a food scale, and track your calories(both what you expend vs. take in).
Aim for a 500 calorie deficit per day. Keep your protein relatively high, 0.8 or 1g per lb of goal weight. 155g per day should be plenty based on your height. Carbs? Fats? Keeping both high can sometimes be counter productive. Pick a horse and ride it. Lower carb diets may be more satiating and get you towards your goal weight quicker but not guaranteed. Higher carbs may leave you feeling hungrier but yield better fuel for good workouts. The amount of information littered across the internet regarding clean, nutritious food is infinite.
The best diet is the one you can stick to. Drink a lot of water and practice good sleep habits.
That covers it. It is really simple, get enough protein, eat less calories than you consume, and don't neglect your vitamin/mineral/fibre needs, try to eat some variety of veg/fruit or take a multivitamin at least. People will tell you about this or that fad diet like all meat or only eating at certain times, at the end of the day the only way they work is because you eat less calories than you burn so there are plenty of ways to get there.
Measure and track everything you eat, preferably by weight, food scales are cheap. I don't know about Cronometer but have used myfitnesspal app. If you drink beer or non-diet soft drinks, you are probably going to want to stop that. If you are strictly tracking and after a few weeks haven't lost, you have probably overestimated your Total Daily Energy Expenditure (TDEE) in the app. Weigh yourself once a week at the same time (e.g. when you first wake up after a morning piss) to track progress, watching the scale every day is pointless can be discouraging because of daily fluctuations (and the fact that what you lose daily is barely measurable but it adds up over time).
It's a marathon and not a sprint — some of those eventual goals you listed will take many many months to reach , so just be prepared to set in with discipline. Start with a smaller goal and go from there, say start with 200 lbs. But I recommend staying tight-lipped. When you tell everyone about your ultimate goal of fighting at 155lb, there's a process of psychological transference where you get some of the reward of having done it already when you have not yet, which only makes it less likely to happen, If that makes sense. In any case, its much better to have people notice on their own after you've made progress than for them to say 'good for you, you can do it' when you tell them you want to lose 20% of your current weight. Also stay active, you aren't going to be building tons of muscle while cutting and at a calorie deficit recovery is harder but make sure whatever you do for fun or fitness already try to do a few times a week, if you are in the gym it will help retain lean mass.
