models look hot in ads how?

[Tears of the sun]

There are many things which take in making a mortal normal human to look like a diva.

cloth stylist - to make sure they have the best of the best clothes.
hair stylist - self explaining.
makeup - to flatten the skin ( remove small marks etc.)

and the biggest one - a photo manipulation software ( everyone can have softwares, it takes eye of an designer to make mortal to a diva. ) try to hire a photo manipulation company for your own photos if you like ( try it, put the images on your facebook profile and see the effect on your friends, even if they have seen you in real life, it works like magic! )