Hi!
I don't normally post but I thought I'd shed some light here for you since I competed in a boxing tournament about two months ago and cut a good amount of water weight!
I was in a tournament where they created 16-man brackets after weigh-ins based on weight, so the goal was just to lose as much weight as possible. I dropped from ~162 to 154 official weight in 2 days. It's actually extremely easy.
Tonight until you go to bed, drink as much water as possible. Like seriously as much as you can handle. There is a delay in your pissing reaction to your water consumption, so when you boost water consumption you still piss a lot the next couple days even if you stop water consumption.
Friday, drink like 64 oz of water. Saturday, 32 oz. Sunday, 12-16 oz. Monday, don't drink anything til you weigh in. Again your body will still be pissing as a reaction of heavier drinking a couple days earlier.
Don't do protein shakes day before/day of. Even though it's low calorie, that soon before weigh-in it's all about actual physical weight of what you consume, and liquids are heavy.
Eat eggs on Sunday morning, and have a quest bar Sunday afternoon (and maybe one more sunday night). Dat fiber might let you squeeze in one extra shit to cut more (seriously, hold off on your poop/piss day of until as soon as you have to leave for the gym to make sure you get as much as you can out!)
Monday, if it's possible, literally don't touch any food or drink until you weigh in. It's gonna suck, but it should be manageable. If it interferes with work then probably best you consume something.
If you're competing Monday, this is probably too extreme to follow cuz you're gonna be too dead even after eating/drinking after. I'll assume it's at least on Tuesday. You can google the right carbs to load on and stuff the night before/etc.
I hope this helps!
-AJ