Plenty of people told me "you'll be fine," "you know more than you think you do" and "only foreign students fail" before I took my boards. Looking back, I appreciate those ego boosts and agree that it was a lot easier to pass than I expected; however, I don't regret any of the work I put in. If nothing else, studying for NAPLEX is a good way to review what you've learned so far and to brush up before starting a residency.
Over the course of about a month, I studied the APhA book, the ASHP case book and reviewed old therapeutics notes as needed. Study the way you would study for any other exam. If you study hard and like knowing that you did your best, do that again. If you usually blow off studying but pass with flying colors anyway, keep it up. Just remember that it's not a bad thing to think of this as the culmination of 6+ years of hard work - because that's exactly what it is.
Congratulations on graduating, and good luck!