When I'm asked to shoot beauty for a client, be it for a makeup gig, hair product, or simply editorial, the first item of business is to select the right model. Yes, she should be somewhat naturally attractive but more importantly, she must be able to pull off a variety of looks and expressions during the shoot itself.
Most models have the misconception that modeling is all about looking sexy. Giving that pouty, sensual stare and they're good to go. Well, for many editorial needs that is what they want. But for a more fashion-oriented client, or a client whose product needs to reach across to a larger number of people, simply being sexy isn't enough. You must also be able to reveal more looks as well.
From coy, to fun, to playful, even maybe apprehensive or confused, as well as that sexy look. A great model is one who can bring all of those looks to you. Her, along with your guidance and ability to light and capture it all of course.
So please stop and take a moment to consider this when choosing a model, and again when actually doing the shoot itself. Ask her to deliver more than just that sexy stare, but be there in support of her doing that! Which, by the way, is part of your being a good director. You're helping to bring some of that out in a model. Don't just assume these things magically happen, it's a collaboration my friends. You do need to 'be there' as well.
Just some advice about achieving a variety of looks when working as a photographer of beauty and as a model.