How should i highlight or add color to my hair ?

i'm getting color added to my hair in a few days & idk how to get it , should i get color juss in my bang ? , thru out my whole head ? , thaa wiz khakifa patch/streak ? , one piece of hair only ? givee me somee ideas please ... i'll except anything . P.S. i'm a teenage girl with a medium length bob hairstyle , i plan on gettin caramel color ! :)