Well if it's self-hate towards appearance, then what works for me is; look at yourself in the mirror, and for each hateful thought that comes to mind, think of a positive one to counteract it. Example: "I'm ugly" can turn into "I am beautiful/handsome/ect"

In a way dude, you are what you say, and I dont mean this in a bad way, but if you start actually thinking positive and saying stuff like the post above me, you'll eventually start thinking that way instead of repeating the same negative thoughts,

I have self hate issues as well. I've been trying to (this kinda worked for myself, tho may work for you or not) doing things I normally or used to think was pointless or stupid. Like simply walking around a park with calm or no music, going out, buying things that I like, etc. Self care I guess, but I keep falling back into self hate sometimes so I'm not sure if you can 100% eradicate it.❤️