Oriental Empires

The four types are:

Conquest
Son of Heaven
Culture
Points
Win three of these to unlock the achievement.

The hardest one of those above is Culture victory since to win that you need to build extra outside building which cost a lot of gold and settling cities near mountains, through technology trees and buildings.

The points one is the easiest, set your turns to 50, automate farms and set cities to growth, population wins a lot of victory points. Difficulty set on easy, focus on fast techs that give authority/culture/farming/edicts and you'll win in 20 to 30 minutes by settling all the cities you can and spamming Next Turn, have a balance between army and positive income so you can buy pavilions and shrines on the mountains for culture points.

Whenever you meet a new power, try and make a non-aggression pact with them right away, they usually last 40 turns which is great since the game ends at turn 50.

Conquest and Son of Heaven are almost the same, while you are going for Khan or Dragon stop at 80~90% conquest victory.

To advance on conquest, destroy your enemies or better yet, submit them into vassal hood.

A vassal counts both for conquest victory AND Son of Heaven.

So, save a few turns before you win by conquest and instead of going for the vassal, force your enemies to recognize you as the Emperor and you'll get Son of Heaven.

Good luck!