Looking for general domination advice

I’ve been winning games on immortal difficulty in both science and culture, but am having a tough time with domination.

To preface I just do standard rules and random maps and civs and it seems like I have to just win by science or culture around turn 300-330 or the remaining civs will win it.

I’ll get to like 3-4 remaining civs when going for domination out of 8 and the last civs standing just seem way too strong to attack them before they win by science or culture. It feels like if you don’t win by turn 330 it’s a wrap regardless of who’s remaining.

For people who go for domination with all win requirements available, can you give me a general outline of your plan of attack?

What does your army look like when you start attacking at the beginning and at what round should you want to conquer your first civ by? Also how are you managing your currency when trying to just pump out units at the beginning ? Do you just go straight for the capital and ignore other cities and make peace right after ?

I’m thinking maybe I’m “keeping” or “razing” cities incorrectly, because by keeping them it seems like amenities and war weariness counteract the gains you are getting but it also feels like you want a friendly territory to upgrade and heal after a battle