Miami has been absolutely dominating at home, amassing a record of 17-3 and playing the kind of defense that has won them two straight titles. The Heat are still primarily an offensive team behind James, Dwyane Wade and Chris Bosh; they rank 2nd in Offensive Rating and 8th in points per game while only being ranked 21st in Pace. Miami still has a 30-12 record, despite being dead last in rebounding, though that could change if Greg Oden could ever get his knees in good enough shape to play substantial amounts of minutes. Oden was really only brought in to help combat Indiana's Roy Hibbert, however, should he stay healthy enough, he could largely contribute for them on the glass and on the defensive end.
Offensively, Miami exploits any and all turnovers, being the most devastating fast break team since the Showtime Lakers; it's an alley oop fest between James and Wade on the fast break and there's very little anybody or any team can do about it. When not in transition, the Heat employ combinations of pick and rolls with James or Wade, isolations with James or Wade, or post ups with James or Bosh. While teams focus in on one of the three star players, there are subtle screens being set in an attempt to get Ray Allen open and help stretch the floor so they can keep those 3 options available without the defense completely collapsing on them. Should teams manage to stick with Ray Allen and still contain the dribble drive with James or Wade, the team will usually find it's 4th or 5th option open on the perimeter, be that Shane Battier or Mario Chalmers, both of which are above average three point shooters and have the ability to get hot in a hurry.
Defensively, Miami rotates exceptionally well and are very quick to close out on open shooters. The Heat's main game plan on defense is to force turnovers, so they play passing lanes early and often and will usually try to pressure the ball handler into a bad decision. This kind of defense has weaknesses against better passing teams like San Antonio, however it should work to perfection against the Lakers and their lackluster passing out of everybody not named Kendall Marshall. Miami will look to exploit that into easy baskets and more frustration out of the Lakers.
In short, the keys for Miami are: LeBron James. The keys for the Lakers are: try not to lose by more than 20.