Thanks to mustang officer 2ndLt W for answering our questions about the transition from enlisted recruit training/boot camp to a law candidate at OCS.
Prior Service Marines
Coming from a reserve unit and applying through an OSO, my application process was very similar to the one that civilians go through. Reservists go through a few small formalities with their units to get permission and approval to apply to OCS and be away from the unit. I just called the OSO and went through the same interview and application process that a civilian would go through by doing a personal interview with the OSO before getting the necessary references and filling out the application.
It’s not the depot (boot camp). You’re not a recruit.

Officer Candidates School is nothing like law school or the rest of the Marine Corps. Getting into the right mindset to be a good candidate is important. The differences between enlisted recruit training/boot camp and OCS were huge. Enlisted recruit training is a place where it’s easy to just become a robot and go through the motions, while OCS is a place where constantly thinking critically about everything from the tasks assigned to the general interactions with other candidates is very important.
Have the right priorities.
At OCS, I had to get back to the mindset of putting others first. Especially with a wife at home and being a law student, I had been always thinking about keeping her and my priorities first. At OCS, and also as a Marine Corps officer in general, it’s much more important to make sure that all other people are taken care of before yourself (even the ones you may not like) or even making sure your close friends or family are taken care of.
Transition back to normal life
Since I went back to school, I had to remember that I was no longer surrounded by the like-minded motivated individuals I became friends with at OCS. Especially as a law student, it’s important to remember the community that you’re going back to is not necessarily friendly to your newfound point of views. I’m sure any law student coming from the heavily liberal law student community knows exactly what I’m referring to.

Challenges specific to prior service Marines?
Prior service Marines need to remember that the majority of the candidates have no clue what is going on, and often this is their first time away from their families. It’s easy to want to scream at the civilian candidates and be angry with them trying to keep up with things that a prior service Marine already thinks of as common sense, but these kids do not have that prior experience and have a much steeper learning curve. Helping the civilian candidates rather than only being angry with them (as hard as that is to do sometimes) will definitely benefit everyone much more.
OCS is not the recruit depot or boot camp for a different service branch. You are constantly evaluated on your willingness to take initiative, make decisions and communicate decisions.