How to change my game?
Jay's advise is good. Even though you mostly play singles mix in some doubles. Be sure to come in to the net after your serves and returns to volley. 1 up 1 back doubles will do you no good in your quest.
Using the wall is a great way to work on your form. I have used the wall on the back of my house and in my garage to work on volleys and half-volleys. Practice the volley at different distances from the wall. You can practice as close as 3 ft. to as far back as you want. Make sure you are using the proper form and grips. Lastly take a playing lesson from a Pro with working on your transition and net play in mind.