Cut the muslin or canvas fabric to the size you want for your backdrop. Keep in mind where you will be setting up your backdrop and how many subjects will be photographed. For example, a family photographer will need a larger backdrop to accommodate the whole family without picking up the room around you.
For a very low-budget photo shoot, use a white or black sheet. The light may be uneven with a sheet backdrop, but it can be used in a pinch with minimal damage to the sheet. For a larger backdrop, clip the sheet together from behind using safety pins or clothes pins.
Cut a piece of canvas to the correct size for your projects. Sketch out what you would like to draw on the backdrop (a seaside scene, rolling fields, etc.) using a pencil.
Paint in the scene using acrylic or oil paints. Allow the backdrop to dry completely before hanging the backdrop.