For my girls' bedroom makeover, I tackled many projects. One of them was adding window trim to their window to add character and depth. See how I did it next ...
First I measured and cut the wood pieces I would need. I used common board, MDF and hardboard.
Next I used a brad nailer to add the boards around the window. I started with the window sill, then the sides, and then the top.
Then I used caulk for the seams, and plastic wood for the nail holes. I sanded the wood filler down before painting it.
Next I primed all the boards with an oil based primer. Then I did 2 coats of Ultra Pure White from Behr in a satin sheen.