From a materials perspective, I was using my Winsor & Newton half pan set as well as some white gouache. For those not familiar, gouache is very similar to watercolour, but with heavier pigment load and thus corresponding opacity. Handy for when you want to cover.
Basically, I started with the "sunny" part of the painting using yellows and reds. Then I went into the sky with various pinks, purples, and blues. The darkest part using indigo. The foreground and the trees were painted with sepia.
The gouache comes in for the stars. Basically, I dipped a toothbrush into the paint and used my thumb to create a paint spatter across the sky. Mostly worked as intended. :)
In any case, this is a fun way to paint, very loose and unconstrained. For this, I painted on a Fabriano Artistico 5" x 7" 140lbs cold pressed block. This is a great paper in these cases because the block gluing on all four edges really helps to prevent buckling and warping of the paper when using a lot of water like this painting did. While my sketchbook is pretty good on that front, it would never hold up to the water volumes and not buckle.