[LT Guppy]

Worry about learning you job and getting your quals first. After that, yes, community service and continuing education always looks good.

Some people will recommend you volunteer for a variety of different platforms (don't just pick destroyers, volunteer for an amphib or other platform).
It used to be that "homesteading" (staying in one geographic location) was frowned upon. That is no longer the case, especially as the Navy looks to save money.