A few make up tips -
Make up does have a big effect on the quality of the photo shoot. Normally the make up artist would have a few assistants that each specialize in a certain area of make up.
Any human being has a few dark spots around the face area, and these can easily be hidden with a little bit of concealer, as the name suggests it conceals the spots giving the skin an overall symmetry.
Foundation is applied on all areas of the face, and sometimes on hands and legs as well (just for the shoots - this is not mandatory make up). Eye liner could be used to remove the look of fatigue, if the model does have that after many hours of shooting.
This is generally the final make up touch that is applied, and the make up specialists usually use lip gloss and pencil to add the finishing to the lipstick.
Make up is something that need not take a lot of time.