It's all about well-behaved hair, imvho.
I can look glamorous. I can, with a LOT of effort, look quite pretty, and sexy even.
I cannot look 'polished' for the life of me. It's my hair. It's neither curly nor straight, just kind of wavy-ish, very very thick and loads of it. It doesn't suit me if I wear it down; it doesn't suit me short (looks like a loo brush). So I have to wear it messily clipped-up ALL THE FUCKING TIME. If I straighten it, it goes limp and makes me look haggard. If I rough-dry it, it looks like I've stuck mmy finger in a socket.
If I pay £30 to get an amazing bouncy blow-dry, it looks quite glam.
It still doesn't look polished.
My style is quite preppy, I'm tall and slim, so the only real thing that destroys ANY ability to look polished is my blooming hair.
I've given up fighting it now tbh.
When I see a pic of eg Carole Middleton, I realise why I will never look polished (say what you llike about their slightly safe style but the Middletons and Carole in particular never look anything other than polished). It's her HAIR: straight and sleek by nature, and well-cut obviously, but just manageable and 'neat' in a way mine has never been.
Natural-looking tan helps. (I'm ghostly pale).
But yeah. Mostly about hair.