Write it in 3rd person.
An outstanding leader .... blah blah blah talk about collateral stuff, or being a role model for med students, whatever
A capable and proficient clinician ... blah blah blah case numbers, our go-to expert for handling complex _____ cases [whatever specialty niche you've carved out or been stuffed into]
An educator and lifelong learner ... blah blah blah play up every bit of teaching you've given to students and residents, if you have any collaterals that apply play that up
If there's space, a summary sentence at the end, something like LT narcusprince is one of our finest clinicians and an outstanding naval officer. He has my highest recommendation for promotion, selection for fellowship training, or additional leadership responsibilities.
Someone there can pull up an old fitrep you can plagiarize. The truth is, as a breathing non-felon LT, you'll pick up LCDR next year unless the fitrep has horrendously negative stuff or a PFA failure on it. Don't exert too much effort polishing it.