I want to make some crewelwork samples into cushions. The crewelwork isn't big enough alone so I need to make a border with mitred corners to make the front bigger before attaching the back/inserting a zip.
It has been years since I did anything like bind a quilt edge but I presume I need to work on those lines.
Can you tell me how to get my mitres perfect please 
. I have googled it but my broadband isn't fast enough to watch much!