If you are a young actor wanting to hone your craft, one of the better books to read is The Actor's Eye's by David Downs. Downs is a faculty member of Northwestern University and a student of the legendary Alvina Krause. Both believe that acting is based on real kinesthic responses to the stimuli in your environment. It is responding truly in the moment on stage that creates compelling performance.
Their technique is not a passive technique - it is purely physical. You will produce a deeper emotional response if you root the emotion in your body and muscles than if you think yourself into being sad. The idea is creating a whole being, a whole character, that will respond openly and honestly to all that is around you.
To use this book as a guide, you have to get on your feet and do all of the exercise outlined therein. The concepts are fairly simple, but unless you can actually apply them you will not fully understand them. Just as with acting itself, you have to allow the experiment to fail a few times so you can find what works. If you feel that you are pretty comfortable with something - do it the opposite way.
What is lost by the attempt? Nothing. You will either find that your first choice was correct and you've gained the confidence and evidence to state that. But if the opposite view works, you've learned something too. Perhaps the best scenario is when you can take pieces of the original choice and add elements of the opposite to create a multi-dimensional character that is not founded in black and white. Complex ideas give an audience more to think about.
So read the book. Try out some of the ideas and don't be afraid to fail. If you don't get it on the first try - no big deal. Your only failure is to not get it at all because you gave up after one try.
Happy Birthday: Brian Blessed (b. 1937)