The best plot will be nothing more than words thrown on a page if the story lacks heart.
Define your own success.
Deleting thousands of words because they weren't usable doesn't mean you made a mistake. It's just the work it took to get where you needed to be.
Tell the story YOU need to tell.
Never forget the feeling of being swept away by a wonderful book.
Always remember it's likely the author thought it was a pile of garbage at one point, too.
Jealousy isn't going to help you finish your novel.
Neither is Twitter.
Criticism isn't always easy to give or receive. Be grateful and be gracious when on either end.
A good writer has learned to polish their craft. A great writer never stops learning.
When you need to step back and remember why you started, what do you tell yourself?