When my husband was in the academy, he struggled a lot. Even though he had always wanted to be a police officer, it was tough. He had moments of doubt in his own abilities, and he had moments where he had to ask God whether he really was where he was supposed to be.
To encourage him, I bought him a small set of scriptures (similar to this) and highlighted any that I thought would help him with a blue highlighter. I figured he could read them at the academy, then when he had his own car he could easily store them away since they were so compact.
It surprised me that there were so many verses that seemed to apply directly to law enforcement, and as I went through the pages and searched for them, I found more and more. This project was inspiring for me, and has been helpful for him.