"If you could say one thing to aspiring novelists, what would you say?"
Everyone hears, "Follow your dream and never give up." I'm a firm believer in dreams, and I don't give up, but my advice would be to make sure you know how to write BEFORE you submit to every agent/editor on the planet.
I get so many submissions that have a great concept for the story, but the writing is too weak. Get a few recommended books on writing, go to workshops, take reputable online classes, get constructive feedback from a contest or two, try to get a published author to read your first chapter and give you some direction.
This is not an "I want it now" kinda business. Wait as long as is necessary and send your best work out. You get one shot, and if ya fire too soon, bang! you're dead...
--Kelly Mortimer, Mortimer Literary Agency - Diabolically Diligent. www.mortimerliterary.com