Add a 1 x 1-1/2-inch piece of wood called a nailer along the top edge of the cabinets. This will serve as your nailing strip so you don't crack your cabinets. Measure the length of each run of the nailer.
Using a miter saw, set at a 45-degree angle, cut pieces of baseboard-type molding to create a riser, which will serve as the crown molding base. Measure different angles to create custom-angled cabinets.
Attach Riser to Nailer
Apply wood glue to the riser and attach it to the nailer with a pneumatic nailing gun loaded with 1-1/2-inch nails. The riser should reach to the ceiling.
Measure Each Riser Section
Measure the run of each riser section.
Measure and Mark Crown Molding
Measure the crown molding on the miter saw and mark it with a pencil.
Cut Crown Molding
With the miter saw still set at a 45-degree angle, cut the crown molding to length. Cut it a little heavy leaving the pencil mark on the molding. You can trim down if necessary.
Run a bead of glue along each piece of molding (image 1). Place the crown molding at the top of the riser so it touches the ceiling and nail it in place to the riser (image 2). Paint or stain to your preference.