I dunno if I would do a battle scene as that is usually some of the most confusing parts of the movie and they don't always show the elements you are looking for.
Here's a few suggestions from the 3 movies [broken up into chapters from the DVD]:
FotR--
Concerning Hobbits [lights, colour, setting, costume, etc. especially]
Rivendell [lights, colour, setting, costume, ((differences in)) body language, etc.]
Caras Galadhon [lights, colour, setting especially]
TTT--
The Banishment of Eomer [body language, setting, lights especially]
Arwen's Fate [colour, costume, editting]
Where is the Horse and the Rider [body language, lights, costume, camera angles, editting, sound]
The Tales That Really Mattered [costume, camera angles, editting, setting, sound]
RotK--
Arwen's Vision [lights, costume, editting, camera angles, sound, colour]
The Lighting of the Beacon's [editting, camera angles, sound, colour]
The Sacrifice of Faramir [camera angles, editting, sound]
The Ride of the Rohirrim [camera angles, editting, sound, light, props, setting]
The Return of the King [camera angles, sound, light, props, setting, costume, body language]
Hope that helps you out, Ellie!

Good luck!