Plot = chain of events that actually happen, pushing the character into the conflict.
Premise = the Big Idea behind the story; the set-up.
Awesome premises are awesome, but we need to know how things escalate from there.
Premise = Story idea. "The realm of Wonder is ruled by a cruel fairy god. None can oppose him. The realm of Wonder is parallel to Earth"
Plot = Stuff happens. "A wingless faerie boy sets out on a quest to defeat the cruel god who rules the realm of Wonder."
-Outdated or classic books (unless you're putting a new twist on it, or it's a retelling, etc.)
-Blockbuster bestsellers (many, many people use these, it makes your story sound less unique)
-Recent-ish (last 5-10ish years)
-Books that match your genre, tone (gritty, lyrical, funny, etc.), & an element or two of your story/plot
-Books that an agent would recognize, but that aren't huge bestsellers
"I'm querying you because you rep fantasy" = not relevant. They already know they rep fantasy.
"I'm querying you because your MSWL says you love gritty sci-fi" = relevant (as long as your story really does fit their wishlist--don't shoehorn it in, they can tell)
"I'm a longtime follower of your Twitter feed; thank you for your generous advice!" = not necessarily relevant, but appreciated if it's sincere.
"I have published articles in xyz well-known magazines; this will be my debut YA."
"I have self-published two prior novels [if your sales numbers are good, include them!], & want to branch into traditional publishing."
"I'm a nurse from Ohio."