Please, give me some roamer advices.

Just like the header says, I am asking for some roamer advices or tips. There is only so much I can do playing instinctively. Recently, I've found myself doing bad as a roamer, and I can't find out the reason why. I always give vision during objectives and engage when needed.

I can't just keep playing like a dumbass who can't think of where to go. Give me directions and such when I encounter some cases.

Maybe when I misjudged the enemy's location and I'm far away from the clash, what do I do? What do I do to avoid this case in the first place?

Or maybe I'm the only one left because I tanked the hits and survived but my teammates didn't.

How do I engage propely? How do I safely give vision? How to initiate a gank? Do I lack communication? Just really, any broad advice as a roamer.