There is one thing that experience has taught me, a realisation that has crystallised in my mind only recently.
That, a really sexy woman always thinks she is average-looking. And that the really sexy women on this earth always hide -- at times deliberately -- behind the veil of simplicity.
The veil, rather the objects of simplicity, could be a pair of specs, plain-looking clothes, unwaxed arms, floaters instead of smart sandals, and so on. They wear this veil, either because they are innocent and don't realise that they are actually masking a potentially jaw-dropping persona; or because they don't care what the world thinks of them; or because they purposely want to stay away from the glare: they want to be judged by what they are and not by how they look.
In the first case, it is the innocence that enhances the sex appeal manifold, while in the latter two cases, it is the I-don't-give-a-fuck attitude that makes them even more irresistible.