Me! get a teacher. All kidding aside, coming up in the business I've worked with trumpet players who worked with Bunny Berigan ,Harry James, Sinatra, etc. etc. , the list goes on and on ,anyway they all said the same thing , you never stop learning,there's always room for improvement, and there's always someone that can do something better than you. So the biggest demon you can have is to stop trying to be best player you can be.