Very thorough, but rely too much on physical health and psychology. Focus on leadership style and ability, but are more concerned with how to get the job done when you get in.
Depends on your commissioning source. USNA and NROTC require an application, in the case of USNA a recommendation from a Congressman, and usually an interview. Then of course 4 years of college. If you're already a graduate, see your local recruiter and attempt to gain a slot at OCS, a 3 month boot camp for Officers in Newport, RI>
Interview questions [1]
Question 1
It's the military, so it's pretty straightforward. Display a desire to lead and show an aptitude through your academic and work background.