A year or so ago, I took an editing course with Kathy Ide, the founder and coordinator of The Christian PEN: Proofreaders and Editors Network. I'd never heard of The Chicago Manual of Style or the fact that editing houses used certain grammar, punctuation, usage and spelling rules.
If I can recommend one book to buy that will clean up your writing so when you submit you might look a tad more professional, I'd tell you to buy Kathy's book, Polishing the "PUGS."
It's a mini version of the huge CMS.
I constantly refer to it but sometimes not enough as my critique friends can attest to.
Family Relationships, "Kinship names"(father, brother, aunt, cousin, etc.) are lowercase when used generically or when preceded by a modifier. EX.: my dad
When used in place of the name, kinship names are capitalized. Ex. "Hey, Dad, are we going fishing today?"
Terms of Endearment: Terms of affection (honey, dear, sweetheart) are always lowercase.
Terms of Respect: Honorific titles are capitalized. But general terms of respect are not. Ex. His/Her/Your majesty
Some basic information but I know once I read this compact book--it made a difference. She lays out the rules simply and easily. No wading through a hard grammar book.
So if you want a good clean-up-- I highly recommend this one take a place on your shelf!