Here’s a tip from @isoscella: Don’t line up your MDF panels with the ceiling or baseboards ... wall for a smooth finish. Here ...

First, remove enough drywall so the trim can span the jamb and wall without rocking. This solves half the problem. But a regular 45-degree miter won't fit even now because the molding has to tilt ...

The fastest and least inexpensive way to improve a home's interior appearance is to install decorative baseboard, crown, and door moldings. The market for interior moldings and installation ...