From my own experience, you should practice with people better than you, get used to being a ball spotter.
Watch and learn, don't get down just cos you may be getting hammered, and watch the improvement, this will help you mentally for matchplay.
As far as tournaments go, I used to go in as many as possible, at first getting beaten so bad was the worst but the more I gained experience the more I learned how to handle myself under pressure.
Then the improvement in matchplay will follow, it's all about dedication and temperament.
As the saying goes.
You have to learn to lose before you can win.
Good luck