I don't think there's a "best" way to get back into it, but I'm sure you have notes, study materials, and things you used to stay current and study, before. Those may be worth a review.
There are courses and programs geared toward CFI renewal, flight reviews, and so on, available from Gleim, Sporty's, etc. These are printed, videos, and online courses, to get a general overview of aviation, or a refresher. It's probably a good idea to go get a fresh flight review, and an instrument proficiency check. Somewhere in there, hit the bricks.