Most of my dreams tend to have something in common. For example, the distance between my old school and my house is always much shorter than it should be. There are also some locations in the town near the school that I'm pretty sure only exist in my dreams. I never visit that place in real life, so when I visit it in my dreams, all the memories I have of it seem to be dug up from previous dreams. I particularly remember one dream where I spent a whole lot of time exploring the place, looking for something. Now when I'm looking for something in the town, I'll just remember that dream, like "oh yeah, that was there", and I find it. In my dreams.
Some places, like the location of my house, seem to be constantly changing, though. Sometimes it's right where it should be, sometimes it's on an island, sometimes in a cave and sometimes it has an extra floor or something like that.