"Keeping the Reader Reading," Part 10
In each scene, a writer should identify the viewpoint character immediately in some manner then place that character within the scene itself. Have him think something which shows that he is now the viewpoint character. In the scene above, the word "forced" is the reader's first clue that we are now in Gard's viewpoint. The rest of the paragraph reinforces his viewpoint.
Gard forced his right fist back into a hand before he knocked Mark's teeth or the side of the door in and pushed the front seat back into position. He locked and closed the door then nodded curtly to his former partner. "I'll call you."
Even if the scene is primarily introspection, the character should still be in a physical place at the beginning. In other words, first show that the viewpoint character is Hamlet, show that he is standing on the battlements of the royal castle, and he's staring at clouds, then let him think about whether he should believe the ghost of his father or not.