|New slope design with guys in a boat|
You can also take one and try to replace the flora and fauna with a similarly oriented flower or animal of your choice and it should work much better than trying to originate the design from a blank template.
The slopes are the easiest to put scenes in if you are having trouble getting all your design on the sides of a double casket. But the scene has to be very linear, like the boat scene above.
Also, another design hint on your larger panels is to think about using half a motif. Some make the mistake of trying to put all of the motifs they want to represent on the panel as spots instead of trying to compose a scene and zoom into the scene. The castle might not fit as a spot but would look great if it was half on the panel at the edge. Same with cars, animals, trees, houses, and other large items. They would look much better partially there - it still tells you that the object is there - but it doesn't cause you problems with white space.