Before working for MAC , you should have some makeup experience / retail experience . Questions I ask before applying foundation concealer etc, how is your skin type are you oily dry combo ? What type of finish are you looking for more matte or satin or dewy ? ( make sure you know the difference between finishes ) to color match I honestly just can tell by looking at somebody but if I'm unsure I swatch on their jaw bone and on their nose . I like to swatch on the nose since its a more promoniate feature. Hope this helps !