Purchase lime green fabric from a craft store in as many yards as desired. Look for clearance fabric that is opaque and has no embellishments.
Designate a large wall for your green screen. Choose a space with a lot of room and no furniture, unless you want it in the shot.
Hang one corner of the fabric high enough so that it will be two to three feet above the subject’s head, or higher if you are doing a wide shot. If you are green screening the floor as well, make sure that the fabric spreads out until it is only a few feet from the camera tripod.
Affix the fabric end to the wall with a clear thumb tack. Pull the fabric taut and keep pinning it at the top until it is completely affixed. The fabric must be ripple-free and perfectly taut without folds, creases or shadows.
Pull the fabric down toward where the floor meets the wall. Making sure the fabric is somewhat taut without creating creases, pin it into place. Do the same for the other side.
Duct tape the fabric to the floor around the edges. This will keep the fabric on the floor in place. Position your camera so that the green screen fills the entire frame.