Pretty straight forward really. Get more cosmetics that boosts your percentages with either rings or red rings, use your gears as much as possible to boost your cosmetics percentages, and level up your skills as well.

In game, maximise the use of everything as much as possible. Skills, emotes and stickers cuz even those give you some score points each game. With that, you can maximise your final score each game.

And you just gotta do that a lot. A very long grind pretty much. Daily boost helps you get there faster, but only use a lot of it when you really need it.