1. The map will tell you about where to go. If the marker is not there, open the map, then open the journal, select the quest, and press "Show on map". It tells you about where to go.
2. Once you are in about the right place, think it through and pay attention. Some no-spoiler examples.
I go to a location. The person is not there but his wife is. I talk to her and she tells me about their work in the mine. Well, there's the mine right there. I go in and walk up to people until I find him.
I am told to go to a place and kill something. No directions are given but it is obvious that it is near town. I use "show on map" to get the right general area. I look at the features and spot the indent that usually means a cave.
Another fed-ex job, deliver a book. I arrive in the intended city no further instructions. How to find this guy? I read the book that I am to deliver to him. The book strongly suggests his line of work so I go to the appropriate place and find him.
My point is that there is enough in the game to figure it out, and for me I regain the feeling of exploration and discovery. If you were thinking about trying it, do so. The compass markers are not nearly as necessary as some believe.