Here are some of the best books on retirement planning:
What Color Is Your Parachute for Retirement by Bolles and Nelson
How to Retire Happy by Stan Hinden
The New Retirement by Cullinane and Fitzgerals
Don’t Work Forever by Steve Vernon
How to Retire Happy, Wild and Free by Ernie J. Zelinski
All of these books are good in their own way; I suggest you pick up one or two of them at your local bookstore or on-line and browse through them. Pick out one or two and start reading. I suggest that you do the exercises that they authors recommend too. The Bolles and Nelson book is particularly good for homework exercises that may help you determine what an ideal retirement looks like for you.