Remove door from hinges. Paint if desired, and let dry
Decide on a design; measure it out with a ruler. For our design, the outer rectangle is inset 1 inch from the door edge and the inner rectangles are 3 1/2 inches from the door edge with 2 1/2 inches between the 2 inner rectangles to clear the knob.
Tape off the design with painters' tape, making the inner edge of the tape the line where you wish the tacks to be.
Check your box of tacks for the measurement per tack. Using a ruler and the marker, measure and mark off along the inner tape edge where each tack will be inserted.
Place awl at each marking, and tap it with the hammer to start a hole. Remove tape.
Starting at the midpoint of each edge of the outer rectangle and working outward, gently tap the tacks into place with hammer. Depending on the tacks' finish, you may wish to cover the hammer tip with a felt furniture pad so it doesn't mar the top of the tack. End with corner tacks.
Once the outer design is complete, tap in tacks on the inner designs.
Blue painters' tape, 1-inch width
Nail-head upholstery tacks (the design shown requires about six hundred 1/2-inch domes and twelve 1-inch squares for the corners)