You can write anything at all about yourself - if you don't know who you are, nobody else will!
It depends whether you are writing to apply for a job or writing a book about yourself. If it's for a job then think of the things you are interested in and what your character is like: eg: interested in sports, active in skiing, digital imagery, like to read and gain knowledge, etc.
Read more: http://wiki.answers.com/Q/How_can_you_write_about_yourself#ixzz27sxYAP3f