Finishing! is the first best thing. The next best thing is when an absolute stranger loves what you wrote, and takes the time to tell another human being about it! (It's unfortunate but you cannot trust your friends and family, precisely because they love you, and they know how hard you've worked, and how disappointed you'll be if your story is a failure, and you might go jump off a bridge and then they'd feel bad and so on...) Further, if this someone is a New York agent, your just might have to go buy a bottle of Dom Perignon to celebrate, even if turns out they are unable to find a publisher. And the last best thing is your next great idea for a plot.