Also consider that if you sort of have an idea of where you are you can go on a bearing to a linear feature that intersects your line of advance (walls, tracks streams etc.) Once you have found that you can follow the feature to an identifiable point (bend in the wall, intersection with another wall, gateway etc.) Then you will have a better idea of where you are.
I think I may have said before, the art of not getting lost is to navigate constantly. Never pass a feature, bend, intersection, change of gradient etc, without accounting for it and at the same time working out what will come next in terms of features and direction of travel. That way, if you enter cloud or fog you should have a good idea of where you were at that point and what bearing to follow. Even if you are following a path, have the compass out all the time in cloud to check the path is going in the direction you expect; in poor visibility it is easy to stray onto the wrong track. Follow the same methodology, what direction should you be going in and what is coming up that may give you another fix? Keep track of elapsed time and speed to work out distance travelled, that way you will know when you should be approaching an identifiable feature to get a fix on your position.