Step 1: What you'll need
- your not-quite-warm-enough jacket of choice
- enough insulating fabric to cover the front and back inside panels (fleece, faux fur, whatever you have)
- buttons (optional, if you want it to be removable)
- marker or chalk that will mark your fabric
- old newspaper
Step 2: Make a simple pattern
Now it's up to you. You can guesstimate the lines and cut away, you can feel for the seams and draw yourself a line to cut, or you can fold the newspaper to make a crease (picture 4) and cut along that. Any way you choose, it doesn't have to be perfect. Also, try to err on the larger side...you can always cut something smaller!
Label your front piece on both sides. I cleverly choose the names "Side A" and "Side B".