Step 10: Continue pinning, folding, and shortening your corners until the fabric is holding
Now's the time to do whatever you can to follow steps 8 and 9 to keep the cloth on the chair securely. Start with one end, work to a corner, and then ensure sharpness for the corner and sometimes take the longest part. Once you finish your first face and angle, however, you'll find that the rest of the chair is comfortable.
When you have finished pinning all sides and corners, take a close look at the chair. If you find that you need to redo a corner or lack a staple part of the chair, go ahead and fix it.