In this post I'll describe how to line a vest. This description is based on the technique that is described in a Burda sewing book I have (in Dutch).
For your information: here you can find this description in a PDF-file.
First the result of the vest, I had no buttons to go with it, will add these later.
The back of the lining is cut 3-4 centimeters from the fold of the fabric. This gives moving space and prevents your outer fabric from pulling.
Sew the center back seam partially: 5 centimeters on the top, and a few centimetres in the waist and on the bottom.
Sew outside of vest as normal, but do not sew the side seams.
Sew lining, without sewing side seams.
Pin and seam vest and lining at front, armholes and back hem. Stitch to the exact seamline of the sideseam, not over it (see next picture)
Make sure you mark the side seam, to be sure that you do not stitch too far.
Clip all round seams, grade seams if your fabric is thick.
Turn the vest by putting your hand through the side seam, pull the front through the shoulder seam.
Repeat for other side, use the same side seam to go through.
This is how it looks, partially turned.
Now pin the seams you want to topstitch later. It is now still possible to reach all seams through the side.
Pin and stitch the side seams of the outer fabric. Be careful not to stitch the lining.
Press the seam.
Pin the lining over the side seam.
You can choose to stitch this seam by hand, or 'stitch in the ditch' from the right side of the vest. The next picture shows the result of stitch in the ditch.