Why not starting about your life? looking back your life, you can see how you created a path on your own and talent you had in your young age and all those mischief's , naughty behavior and lots of memory. There is no best way to re-live those moments and also to know more about yourself. Believe me or not, there is some magic in writing. May be that's why all great man had supreme believe in writing about themselves or their vision , dreams and more.
There is no one to hear, just you and your life. So , the best time for being really honest on you and everything involved in your life. You can write lot of things that can't be shared with others. The fear, love, lose, disappointment, angry and every emotions of your life will get an answer when you are writing.
There are many things that can't be expressed but only can be felt and writing is definitely one thing. When writing you will go to your deepest heart, where you will find lot of truth about you. We tend to forget lot about us as we grow up like eating along with all families & friends on top roof with open face. Little little moments but off a great value.
Just try it, you will find an answer for your life.
Cheers! and good night