Poppetry is a form of sympathetic magic. Everything from the energy you create it with, to the things you choose to stuff it with will effect how it works. For something such as bringing a lover back, I would suggest adding some rose petals, violet oil, ginger, cinnamon, or other herbs related to love.
When using it, you could use pins to direct energy to the heart area and head, while focusing on warm loving thoughts, and visualize them returning to you. You could hug it (yes I know that sounds corny) and kiss it, speak to it in an alluring manner, or anything else you can think of that would project your will to be with them happily. Best wishes ;)