In my opinion the best LOR choices will be determined by two factors. First, what program you are gunning for (BDCP, OCS, NROTC). Second, what designator you're gunning for.
In general you should get LOR's from people that know you very well. They should demonstrate that you possess the skills a Naval officer needs to be successful. If you held a leadership position (team captain or something) have the advisor/coach write a LOR. If you worked efficiently under stress at your job, have your boss write one.
Once you have those down, you should look into some of the eye candy LOR's. People in high-ranking positions that may not know you that well. This is where you would tailor the LOR's to what ever you're applying for. If you're shooting for OCS -> SPECWAR, find, talk and train with a former SEAL. If you're shooting for BDCP -> SNA, find a former fighter pilot.
I've heard that some people were given forms by their NRD to give to the people writing LOR.
I only submitted two LOR's and they both were from people that knew me very well. I wasn't given anything to send them, so when I asked them I gave them a general idea of what the LOR needed. I slightly altered the general idea so that the two LOR's would demonstrate my abilities fully. My third LOR was from an employer (mandatory), which was my dad so I didn't put any weight on it. h
I knew some prior military people, but didn't know them well enough to ask for a LOR. Look in the stats sticky. People often listed who wrote them LOR's. This should give you an idea of what is making a successful kit these days.
