[quote=Sherlock Holmes]
Great. Now let's see you do a master study of one of those (or even just explain to me why they work compositionally) and actually do something impressive. 
[/quote]

I am a total novice at breaking down composition, (I've never even taken a color theory lesson, let alone tried to break down another artist's composition), but I'd like to give this a shot. 

The Mona Lisa's earthy tones are all it needs on the color front. This piece shows how using a limited palette is pleasing on the eyes, and the soft colors of the skin are offset nicely by the lighting on the material of her sleeves, and the embroidery of her undershirt. 

The next piece, although a replica was hanging in front of my face every day as I went into my middle school, I couldn't tell you the name of it. I don't really see why this painting is even interesting, and it certainly doesn't catch my eye in a good way. 

The piece thereafter I find to be done very well. The ever present curves in the painting give a soft feeling to a painting that could otherwise seem cluttered. I also enjoyed the use of shadows in this one.

This last piece is my personal favorite. The drab colors of the marshy looking area around her really set off the bright center of the painting. The details are great, and the cloth draping over the side of the watercraft really catches the eye. White clothing was a perfect choice for the female, and I love how the one candle that is lit is being blown in the breeze.