As Calvin taught in the opening of The Institutes of Christian Religion, we cannot truly know ourselves until we know God. A corollary to that principle (though it must be stated more carefully) is that we cannot see ourselves accurately without the mirror of others' _honest and loving _perceptions reflecting back to us.
For women, Joe Carter has written a great piece called 9 Things You Should Know about Female Body Image Issues. In the post, he included the fascinating video below. A forensic artist first draws women from descriptions of themselves, then sketches another portrait as other people describe them. The contrast is stunning and revealing.
Ladies, be sure to read the post and especially the last point.