The last step should seem obvious. Once you’ve completed trimming, you need to add paint and seal up any gaps. We like hammered-texture paints because they are durable, and the textured finish helps obscure any imperfections in our trim job. We also have used automotive seam sealer, as well as grey caulking from the local hardware store. If you do need to use body filler, use a quality brand that contains only hydrophobic fillers—and use it sparingly.