An Artist's Sketchbook

Heres my plein air from Sunday. I am still having trouble getting good pictures, but this will work.
This is the playground across the street from my house. It was an overcast day, but every ten minutes or so the sun would break through and gave me some nice shadows.
I tried to limit my palette to the following colors: Ultramarine Blue, Cadnium Yellow Light, Burnt Umber, Alizarin Crimson, Titanium White and Ivory Black. I am still trying to wrap my brain around color temperature, I understand it, but it tends to get lost on me during the painting process. I will post this on wetcanvas for some advice. I am sure someone will be able to advise me on how to warm up the painting, being that it is mostly cool colors.