For more detailed information and examples, please see The Associated Press Stylebook (55th edition). Capitalization is discussed on various pages including, but not limited to, pages 3, 27, 38-39, 44-45, 59, 60, 70, 114, 127-128, 173, and 297-298.
Headlines take sentence case.
Man bites dog
New theory from dead Einstein
War on Christmas fake news
Only capitalize a department when it includes either a proper noun or when it is the official, formal name.
The professor was not a part of the English department, but from the department of communications.
There are 12 tenured faculty members in the California State University, San Bernardino, Department of Communication Studies.
Use lower case and periods to define clock time.
At 8 a.m. the meeting began.
It didn't conclude until 1:15 p.m.
But there was a break at noon for lunch.
I didn't make it to bed before midnight.
Capitalize a title directly preceding a proper noun, but not when used alone.
We watched President Morales walk across the lawn.
We watched the president walk across the lawn.
Do not capitalize an occupational description.
The speech was given by astronaut Kayla Barron.
The audience was enthralled by writer Kevin Henkes's anecdotes.