Tips for getting into open world games?

Time lots of time is what you need, and take the games slow don't rush through quests and remember to explore as much as possible. Pay attention to the lore and stories around you.

My recommendation is play something that has a story line that appeals to you

start with something with more directions like rd2

I agree, sometimes guides can spoil the adventure of a game.

A lot of this comes down to the specific game. I wouldnt hesitate to look up some guides or watch some streams of the game. Ultimately dont force it if the game isnt for you. First and foremost you should enjoy what you play.