For this DIY fabric wallpaper project, you'll need water, cornstarch, a big brush (or a paint roller if you want to do a larger wall), scissors, and a craft knife if you have obstacles like we did. Boil 4 cups of water in a pot. Mix about 3/8 cup cornstarch with a little water in a small bowl until the powder is dissolved. Add the cornstarch mixture to the water slowly while stirring. Boil until thickened and then let it cool. Brush the entire door with paste, then begin applying fabric from the top down, adjusting and smoothing as you go. If you like, you can brush another coat of paste over the entire door, decoupage style.