A good tip would be to create pre-generated mental ideas in your head of dream scenes before you sleep. Just think of how things look. Detail is not necessarily, only the basic structure and mental concept. The mind is wonderful in its ability to fill in the gaps in your visualization. A good way to practice dream-scene shifts in dreams would be to walk from door to door in an indoor building, and loudly declaring mentally what the next room will look like. Examples are: "empty blue room", "long white hallway", "bare closet", "red bedroom". The list goes on and on.