There are several reasons a homeowner might want to project an image onto a wall. But no matter the reason, all you need is a good projector, with a sufficient light source, and a large wall clear of objects. If you are planning to trace a design onto the wall, use a soft-lead pencil to trace the design!
Buy or rent a good projector with a minimum rating of 2000 lumens (the higher the better).
Prepare an image to be projected following the instructions of the projector manufacturer. If you are projecting an image that will be used as a wall stencil, keep in mind that a simple high-contrast image will work best.
Darken the room so that the image from the projector provides the majority of the light.
Project your image onto the wall. Adjust the distance from the projector to the wall in order to get the size that you desire. If you are projecting slides or a movie, choose a wall that can be comfortably viewed by an audience. Make sure it smooth and devoid of distracting colors and designs. Light colored walls usually provide better image contrast.
Make certain that the projector is sitting on a firm surface and that it will not be disturbed or moved. If projecting an image that will be traced from the wall. Start tracing your image at the top and work your way down--this helps prevent smudging of pencil lines as you work.