Naturalism and Stanislavski
Russian practitioner, Konstantin Stanislavski's ideas are very influential. He believed in naturalistic performances that were as realistic as possible, and invented techniques that you can use.
Stanislavski’s techniques
The System
This term refers to the methods used by Stanislavski to foster a good performance in his actors. It focuses mainly on helping an actor recall the emotions needed for a role. Don’t confuse ‘method acting’ with the System. Method acting is how Stanislavksi’s work was interpreted by others, in particular, actors and directors in the film industry.
Given circumstances
The given circumstances are the information about the character that you start off with and the play as a whole. How old is the character? What’s their situation in the play and in relation to the other characters? Are there any notes provided about the play and its characters? Such notes and stage directions may not tell you everything you need to build a character but they are the starting point from which you’ll work to examine the other questions.