Marilyn Monroe had magnetic sexuality. As women, (okay cute gay boys too), I think it's important that we are constantly working on some type of sexual intelligence and awareness... (okay i guess i do mean everybody!) Emotional skills are like oxygen -- invisible, and unnoticed unless missing.
I think that self-acceptance is a really big part of sexual intelligence and feeling "sexy." If you don't love and accept your own body, how do you expect a partner to do so? If you think you're a boring person, how do you expect someone else to find you interesting? You have to highlight your own strengths and stop comparing them to societal norms. Easier said than done, but if you can do it -- I think it allows us to get to a feeling of freedom, and therefore, self-acceptable... and therefore, lots of "feeling sexy."