To be certified by the Federal Aviation Administration (FAA) as a private pilot, student pilots must be at least 17 years old (for most types of aircraft), although they can begin training when they're younger than that. They must be able to communicate in English -- read, write, speak and understand the language. Student pilots also need to enlist a certified flight instructor (CFI) to oversee their training and endorse their logbooks. That means when they acquire certain skill sets or complete important new maneuvers, their instructor makes note of it in his or her logbooks. When the student is ready for solo flight, the instructor will note that, too.
Private pilots usually must complete a minimum 40 hours of flight time, though some flight schools are more meticulously structured and rigorously certified by the FAA, so their minimum is 35. Most student pilots, however, still need more than the 35 to 40 hours before they're fully prepared. Estimates vary, but many fall within the range of 60 to 75 hours [source: FAA]. At a minimum, 20 of those hours are flown with the instructor -- who can take over if necessary with newer students -- and 10 of those hours are flown as supervised solos.
At some point, student pilots seeking private certification also need to visit an aviation medical examiner certified by the FAA for a physical. They'll continue having medical examinations on an ongoing basis (every five years if you're under 40 and every two years if you're over) to ensure their health status is still up to standards. Similarly, a private pilot may periodically need to undergo proficiency checks and flight reviews to continue flying, especially if he or she doesn't fly regularly.
Next up, it's time to train.