At the end of each season, I take a pencil and paper and make a brutally honest appraisal of the state of my game. If you're serious about wanting to improve your play, you should do the same thing.
Divide your game into driving, fairway woods, long irons, middle irons, short irons, wedge play, bunker play, chipping, putting, and trouble play. Then give yourself a handicap in each area. If you're a 15-handicap overall but have a reputation as one of the best putters in your club, go ahead and give yourself a 5 or maybe even a scratch handicap in putting. But be honest on the other side too - if bunkers have you completely baffled, don't rate yourself better than a 30 in the sand.
This exercise in honesty will do two things for you. Number one, it will instill you with a feeling of confidence in the areas of your game that are relatively sound. Even if you already have that confidence, the exercise of actually writing a low number next to your strengths will reinforce the feeling. Secondly, by coldly and candidly recognizing your weaknesses you'll be taking the first step toward strengthening them. From this point, you can establish a game-improvement agenda for the next season - lessons, drills, golf school, a practice programme, etc. Whateverit may be, it should focus on these acknowledged weak points of your game.