An acting teacher of mine frequently said the same thing after a boring scene, "You have not asked interesting questions of your character."  As an actor you must ask yourself questions about your character.  Yes, you should probably start with Uta Hagen's 10 character questions (from Respect for Acting) but then you must go further.  You must go much, much further.  I am sure Ms. Hagen would have agreed with me.  The ten questions are a start to get us used to asking ourselves questions.

 
Say my character is a gas station attendant. I might only have one line to say in the play, but my character's life is the most important life to him.  A list of questions off the top of my head right now could consist of the following.  How did I get this job?  Is this what I really want to do?  How many other jobs did I have before this one?  What was the high point of my life?  What was the low point?  What is my favorite color?  When is the last time I had sex?  Was it any good?  What was the last meal I had?  Was it any good?

 
I would answer these questions and see how they influence my line reading.  Then I would ask more questions.  Everyday, I would ask myself other questions and explore the possibilities.  If you ask tougher questions, you will find out more about your character.

 
One day after rehearsal, get some cast members to play a game of Truth.  Sit around in a circle and ask probing tough questions of each other's character.  Answer quickly with a story from your character's life.  All these answers are fantasy because the questions are not from the given circumstances of the play.  Whatever you create, you must believe in. Have you ever killed anything?  What will you miss most about life when you are dying?  What will you never forgive your father for?  Remember, you must answer quickly and with a story from your character's past. Questions like this will show you so much about your character.  It will also tie you to the character because your answers will have something to do with your own life.  Creating these pseudo fictionalized facts will join you to your character.

The Actor, a Script, and an Ox - Excerpts 1

"When the question is common, the answer is also common."  Mumon

 
Ask someone "How are you?"  He will probably answer, "O.K., and yourself?"  Ask the same person, "If you could make love to anyone in the world right now, who would it be and why?"  You would probably get a more animated answer.