If you mean Civ 6, Tourism is the keyword for Cultural Victory. Although there are some formulas and rules, to make a long story short, increase your Tourism output as much as possible. You may see what provides Tourism on this page, but I think three things (Great Works [including Artifacts and Relics], National Parks, and Rock Bands) are most important. And because you must purchase Naturalists and Rock Bands with Faith, you should gather much Faith for Cultural Victory. Also, don't forget about Appeal when constructing National Parks.

There are too many recommendable civilizations. So, let me list only some of them.

America (especially under Bull Moose): Double Tourism from Unique Building, and Bull Moose provides Culture and Appeal bonuses.

Brazil: Rainforest tiles provide an Appeal bonus, and Unique Project can be very helpful. Pedro II's Leader Bonus is also great for recruiting more Great People.

Canada: Mountie is not born for war but for building National Parks. Ice Hockey Rink is can also be helpful.

China (especially under Mandate of Heaven): Great Wall is also Great for Cultural Victory. And Mandate of Heaven can construct early Wonders, which provide Tourism, easily. Try to check the Wonder list and find some useful ones for Cultural Victory.

Ethiopia: One of the strongest Civilizations in the game regarding Faith-generating. The allowance for purchasing Archaeologists and Archaeological Museums is the cherry on top.

France: Born for Cultural Victory.

Germany (under Ludwig II): Just check Ludwig's Leader Bonus.

Khmer: Pour the massive Faith to Naturalist and Rock Band. And I believe you already know that Unique Building provides Tourism.

Russia: Use Lavra well. I strongly recommend choosing the Dance of the Aurora pantheon, entering the Classical Era with the Golden Age, and using Monumentality dedication.

Sweden: You don't need to worry about the Theming bonus, and Unique Tile Improvement can be strong if you know how to use it right.

Vietnam: You must construct additional Thànhs!

Thanks for the suggestions. :) This victory type has genuinely been a pain in the butt to acquire, but I hope with these tips I can finally clear this off my bucket list. Thanks again :)

P.S The main thing I struggle with are great work slots.

@Doughy Rozo No problem! It's always happy to talk about the topics I'm interested in. :)

If Great Work slots bother you, you may check this page. There is every building and Wonder that provides the slot. And it is possible to achieve Cultural Victory without Great Works(this doesn't mean that Great Works are useless, though). While a single Great Work provides only a dozen Tourism per turn, one Rock Band can provide hundreds or even thousands of Tourism in a single turn. The problem is, however, that Rock Band must be purchased with Faith, and its cost is not cheap. This is why the good output of Faith is essential for Cultural Victory.