My players consist exclusively of theatre majors. It's strange, though, that it is incredibly difficult to get them to role play. Any time I try to get them in a situation where they don't need to use their powers or skills they scratch their heads and wonder why they aren't killing anything. There are three techniques that can be used to engage those players that can't quite get into the role play portion of a role-playing game.
1. "Is this what your character would do?"
I ask this question when the player is using too much metagame thinking. Sure, Patrick knows that there's an enemy around the corner, but does Rune, his warforged warden? This also comes in handy when players are doing morally dubious things.
"The shopkeeper isn't being receptive to your haggling; you'll pay full price"
"Then I kill the shopkeeper"
"Really? Is your character so morally corrupt and socially inept to kill someone for such a trivial reason?"
"I pay full price..."
Situations like this happen when players think too much along the lines of "this is a game" and less about the role their character plays in a larger world.
2. "What does that look like?"
Another easy way to get your players thinking as their characters is by asking them to describe their actions. This is a great way to get players started in roleplaying. Model the behavior by describing enemy actions, then tell the player to elaborate their action. "I use Magic Missile" doesn't sound as good as "Green jets of energy shoot from Thuul's wand. They arc through the air as they seek Thuul's target. When they strike, a light green plume leaves the Wraith's body." Small steps like this, and during skill checks and skill challenges, creates an environment where you can continue to push their role-playing.
3. Mouseguard up the place a little bit.
I just started a SWSE game with a couple of people from my DnD4e group. As we did our cooperative character creation (ala DM Samuel), I asked my role-play light players what their character's instinct and belief were. Then, right before their mission, I had them create a goal. I rewarded the players with role-play xp. These Mouseguard-esque elements really show players that their characters are not super-versions of themselves; they are different people with different thoughts, beliefs, and skills than their players.
This is by no means an exhaustive list, but these three ways have really upped the amount of role play in my sessions. If you have any other suggestions, or plain 'ol questions or comments, feel free to drop them off in the comments section!