[hirofkd]

I guess it's too late for this project, but for the next one, try using a small flat brush and apply either GSI Creos (formerly Gunze)'s Mr. Surfacer (in a bottle) or your primer which you can spray into a paper cup. That way, you only add primer to the areas where you're fixing (i.e. sink marks, seam lines, gaps, puttied areas etc.), and the rest of the details will remain crisp and sharp. Repeat this prime-smooth-check process several times until you are comfortable with the finish. After body prep is done, follow the body priming instructions other members have suggested.

Mr. Surfacer bottle lasts for a dozen of car models, and you can also save spray primer in a long run.