Rafter tails (ends) not in a perfectly straight line.
For those of you with an overhang to your roof line, you'll want to apply a flat soffit to the underside of the overhang. Begin by snapping a level chalk line on the wall around the entire building. The chalk-line should correspond to the height of the bottom end of the rafter tails. This will be the guideline to which you will attach the 1 x 4 ledger board.
Attach the ledger board with 16d HDG nails. The bottom of the ledger should be on the chalk line.
Nail 2 x 4's level from the rafter tails, toe-nailed into the ledger board to create a frame at 24 inches on center. (Joist hangers can also be used to attach the 2 x 4's to the ledger)
Measure and cut exterior grade plywood to the width of the soffit and nail it to the framing with 8d HDG nails.
Nail a 1 x 6 facia board to seal and trim the end grain of the rafter tails.
A crown molding added on top of the facia will dress up the facia but should be attached so it will line up smoothly with the slope of the roof. To accomplish this smoothly, place a straight edge down the slope of the roof overhanging the eave. Butt the crown molding up against the straight edge and nail it into place with finishing nails.