Depending on your own comfort level with the materiel it is allowable and not unusual for you to complete home study courses instead of attending ground schools. Explain your plan to your CFI. Several companies offer suitable textbooks, including Cessna and Jeppeson.

1) Buy the textbook and workbook.
2) Read the text, do the workbook, keep a running list of any questions you have.
3) Review your questions with your instructor (expect to pay him for this time).
4) Once you have completed the book, buy the red Gliem written test prep book. Study this book, take the practice test, then take your actual written test.

Your CFI will need to review your knowledge to his satisfaction prior to signing you off for the written test and then the checkride.

You can repeat this process for PVT, IRA, and then COMM.