Let's start with those family terms, including "mom," "dad," "aunt," and "grandmother." Capitalize the term when using it as a proper name:
"Do I have to, Mom?"
You should also capitalize when the term comes before a given name:
"Go help Aunt Betty find her contacts."
However, if you're not using the term as a proper name, don't capitalize:
"You should tell your other aunts about your engagement."
"My dad told me to stop chewing my nails."
“Gregory, Lisa’s uncle, had to leave early.”
Other kinds of titles follow similar rules. When the title comes before a name, capitalize it:
“Lieutenant Harvey was one of the pallbearers.”
“Vice President Joe Biden was born in Scranton, Pennsylvania.”
When the title comes after a name, capitalize it when it describes a specific person:
“Vivian Langly, the Provost, led the faculty meeting.”
But don’t capitalize when the title itself is more general:
“Vivian Langly, a provost at a university, served on the community board.”
When titles stand alone without names, they aren’t capitalized:
“Many of our graduates go on to become sergeants.”
“We had to elect a president for our organization.”
However, if the title clearly refers to a specific individual, then capitalize it:
“The Mayor denied the accusations.”
Some style manuals stipulate that prestigious titles—such as President of the United States, Secretary of State, or Senator—should always be capitalized even when they stand alone. Other manuals recommend these titles be treated like any other, and should not be capitalized unless followed by a name. You’ll have to decide what’s right given your audience.
Unfortunately, there are no fancy tricks in remembering these quirky little rules. Look them up as you need to; they’ll eventually stick.