You can over complicate everything with techniques; when you're in the moment, you have to feel that you are that character, that you're feeling the pain or the happiness or whatever it is that they're feeling in that moment. Usually the authenticity will manifest itself.
Each form of the acting is different. I think it keeps your mind active. TV, film and theater are different disciplines, as are independent films, opposed to studio films. There are differences in the size and the genre, or a period drama as opposed to a contemporary drama, or the types of characters.
There's always a connection to be made whether you're playing a psychopath or whatever. It doesn't really matter; you've got to find this thing that you relate to with each character otherwise you're missing something.
I'm quite good at switching off and sometimes I forget who I am in a character.
It's never the practice to shoot the scenes in the proper order. Sometimes you shoot the final scenes of a film before you've even started the beginning. So you get good at it because you have to sort of just eliminate the memories of something you've done as an actor, which you haven't done as the character yet. But it sometimes is a bit of a mind-f**k.