Answered[ Edited ]
I would suggest keeping your brows nourished to promote the growth of the hair. In the meantime you can use a great pencil to create fuller brows. I would suggest the Anastasia Brow Enhancing Serum because it really has deep conditioning ingredients to promote healthy fuller brows. You would apply this gel like serum 1-2 times a day. I like how it dries quickly so that you can apply your brow product over it.
I also would recommend that you try the Dior Backstage Brow Design Brow Shaping Stencils Kit because this kit has the brow shapes already made for you! If you have over plucked and are missing the full shape you can use the appropriate size to match your brow. This kit also comes with two pencils (one is a light blondish brown and another in brown) to fill in your brow. I found these really helpful if you are not sure what eyebrow shape you are looking for.
It will be hard at first, because if you have dark brow hairs you might want to pluck them as they're growing in when they're in the faze where you only see the spec of a hair follicle. So you have to fight that urge to allow the serum to do its job.