1. Purchase a stretcher or build a frame. Canvas frames are also sometimes referred to as stretcher bars, which feature pre-cut slats that you can slip together to create the frame.

2. Get the other necessary materials to complete the job. You'll need a few basic tools to complete a canvas stretching job properly.

3. Center your frame on the canvas. Lay the canvas out flat on your work surface and center the frame on top of it. 

4. Stretch the longest sides of the canvas first. Start with the longest side of the canvas closest to you and fold it in. Insert three staples in the center of that side of the frame, along the bottom edge of the frame.

5. Stretch the shorter sides. Go to one of the unstapled sides and give the canvas a good solid pull, fold it over, and insert two staples, attaching the canvas to the frame. Do the same thing to the other short side.

6. Stretch the corners. Go back to the first side you started stretching and work from your center staples out to each corner. Pull a piece of loose canvas, stretch it down, and insert a staple. Go slowly, stretching a little bit from the opposite side of the bar at a time. Continue pulling and stapling pieces of the canvas moving around the canvas edges in the same order as before.

7. Fold and staple the corners. Tuck one side of the corner under the other, pulling tight, so that one straight edge is just even with the corner. Pull the corners very firmly. This is the final tightening, making it the most important. Be firm and even.

8. Finish stapling the canvas. Go around the canvas and pound all your staples with a hammer to make sure everything is flush with the frame. You don't want rough staples around the edges while you are working. If you see a need for more staples, take a minute to fix a few more in.