Here's a tutorial for how to add the pocket tabs. I think they look great on the Archer shirt, but would be adorable added to pouch pockets on a 60s shift dress. Or perhaps the back pocket of fitted trousers?
The dimensions used for this tutorial are from the Archer pocket, which if you don't have are 22cm x 13.5cm with two fold lines ~3cm apart (see diagram). However, feel free to use on whatever pocket you have!