Things I can do to prepare for enlistment in active duty Navy for MA?

Hello I am currently working on my ociates degree in criminal justice. A friend and me might be joining the Navy after college and go active for MA for a few years. Is there anything that I could do to or learn that would help me better to prepare for this job? Any manuals, cles, or anything else out there? Would it be beneficial to do DEP program even though I will be able to get e-3 with ociates degree anyways? Any Navy MA's have any advice for me? Any advice on how I can get the most out of the time I will be as a MA? Thanks in advance.