When building rooms, try to allow characters some freedom of movement. Do not create paths and trails that force you to go a certain way without any choices. Try and let characters get from point A to point B in a number of different ways, if possible. One suggestion for this is to have one pathway through part of your area, using exit, extra, and room descriptions to show where the path lies. This way, observant players will be able to find the path easily, whereas those players that are not quite as observant will get lost much more easily. Such hints can be hidden two or three extra descriptions deep and be as small as a scrape on the side of a tree, a thread on a bush, or whatever.