Mine en Scene is about communicating certain messages to the audience using what's in the frame. This could be using setting & props, costume, hair & make-up, character's facial expressions & body language, lighting & colour and the positing of characters within the scene.
The setting and props are important. Setting is where it all takes place, it sets the atmosphere. A lot can be communicated just from the background. For example, a desert for a western is very stereotypical. This is because typically it's looked at as a place where heroes are made and villains tend to rule, until of course the hero rises up against them. In contrast to a city scape where there could be multitude of characters, the way it's communicated would now depend on lighting what part of the city we see. However, a city scape is normally looked as the concrete jungle, it's difficult to get to the higher end of society there and so we are ofter positioned with characters that we see fighting there way up.
The props a character has can also tell us things about the character or even the area or situation they're in. For a upper-class woman, it could be an expensive handbag, using colours such as gold on the zips and things. This would discretely communicate that the character is wealthy and probably wants everyone to know, as they're showing it off with the handbag. Other props could be in the background, a character doesn't have to carry them. A good example of this is in Alfred Hitchcock's "Psycho" in the parlour scene. Marion is sitting behind a large pitcher of milk. Though she doesn't drink any of the milk, we can relate the pitcher to herself. The pitcher is a white colour, which depicts innocence and purity, telling us about Marion's current mental state. yet the shape is curvy and smooth which we can associate with the body shape of Marion, it's almost planting seeds for what's later to come, when we later see her exposed in the shower.
Costume, hair and make-up can tell us about the character and their personality. Depending on the costume, we can see if they're upper, lower or middle class. We can also see if they're neat or messy depending on the state of their clothes.
The hair can tell us about their mental state and personality. We can see a character decent into insanity just from their state of their hair getting progressively messier into the film. It's not always insanity that messy hair indicates in movies. In Skyfall, Bond is lost in himself and doesn't seem to be in his best state, physically and mentally. His hair is messy and his facial hair is unshaven, before he begins to fix himself and straightens up, and his hair becomes neater as he does so.
Facial expression & body language are straight forward ways of telling an audience about a character. Though it can be hard getting an actor to play the character exactly how the director wants them. The focus on the facial expressions and body language (as with everything) depends on how the director uses the camera. So emphasis can added or lessened with different angles and shots, such as a close-up.
The lighting and colour and highly important for mise en scene. This is because with different colours, different messages are communicated. E.g. Red=lust or anger, purple=wealth, mystery or frustration, black= Evil or sadness and white=innocence or purity. There are other meaning for those colours also, but those are some of the main ones.
Lighting can completely change a scene. A lot of backlight can create a silhouette, often used in noir films because it's very dark. A lot of key light and filler can create a happier atmosphere, often used in rom-coms.
The positioning of a character is crucial. It can tell the audience how close they are mentally by portraying it physically. If they're mentality far apart they might be on opposite sides of a diner table, like in American Beauty or this scene in the TV series Breaking Bad.
If a character is standing on a step or something that makes that character higher up than others, then the one on the step could be in a higher class or financial or spiritually higher state than the others.