Michael, prior to enlisting in the military, you will be given a test to assess your aptitude to succeed in various fields. I do not know how the military scores this for military police.
I worked at the SA Airport PD with many former military police officers. I also had occasion to call out the MPs for misbehaving military personnel. In general, the things that make good police officers, beyond the physical, are the following: decisiveness -ability to make good decisions, quickly. Report writing - ability to identify the key elements of the offense, and make sure they are included in the report - and to tell the story in chronological order. People skills - ability to talk to people, and, get them to talk to you, voluntarily. Legal -ability to learn a complex body of laws, and apply it when faced with various situations. Personal - your personal life is drama-free, to the extent possible. You don't want to be distracted at work worrying about personal problems. This includes having your financial affairs in order . Self confidence - I have seen low ranking military police have to take control of high ranking military officials - you cannot be easily intimidated by them. Leadership - ability to take control of situations.
A lot of this will be taught to you in MP school. If you want to be an MP, I encourage you to discuss this with a recruiter. Take a practice test and see where you stand. If you need help studying to raise your score, get back with me - I have test-taking tips.
Best of luck!
To start things off, will need to be elisted in the branch of the military of which you would like to become an MP. Once through basic training, then there will be additional training to become an MP which, if your recruiter is worth their salt, you will be taken into almost automatically (provided you are able to pass the qualifying tests to become eligible to be an MP).
Jordan recommends the following next steps: