Print a star, about 1” tall on cardstock, and cut it out with an x-acto knife. If you do not wish to use a stencil, you can paint the stars free-hand.
Tape the frame of your window to avoid paint messes. (Optional)
Paint stars on the upper right-hand side of the back of the window. Be sure it is the upper right-hand side, and on the back side of the window. This ensures the stars are the correct direction when finished. Allow the paint to dry completely.
Lightly paint blue over top of the stars. This is your background. Do not try to paint over the same spot while it is wet—it will take off your stars! Allow to dry completely, and paint a second coat if needed.
Paint on the stripes, alternating red and white. Allow to dry completely and apply a second coat if needed.
Paint a coating of Mod Podge onto the painted portions of the window. This will seal the paint, and prevent chipping from the weather if you plan to decorate with this piece outside.
If you taped the outside of your frame, take it off after all of the paint is dry.
Find a good spot for your American Flag Painted Window for everyone to admire!