-inexpensive small paint brush
1. Print your textile pattern on text-weight paper. If you’d prefer not to print a pattern from the book or one you find on the web, you can also use light-weight patterned paper you buy from a store here (gift wrap and wallpaper work well, too!) Then lay the light-switch cover face up on the blank side of the sheet. Trace around the inside and outside edges with the pencil. Cut out, leaving about a 1/2″ border around the outer traced line. Notch the corners (outside the lines) to make folding easier. Use the X-Acto knife to cut out the inner rectangle along the lines. (books to look at Flora and Folk)
2. using a paint brush, cover the light-switch cover with glue. Working quickly and carefully, line up the paper and pat it down on the cover. Brush glue on the back sides of the paper flaps and fold them neatly to the back side of the cover, pressing out any wrinkles.
3. Allow your light-switch cover to dry, according to the glue’s directions, and then reinstall on your wall. Don’t worry about the screw holes. Simply feel around and poke through the paper with the screws when you reinstall.
(orginally from Designsponge.com)