I'm often asked what palette/paint I use. Well mainly they are from a UK manufacturer called Winsor and Newton (although I think they are actually made in France now). The colours mainly used are...
Neutral Tint (for getting those darks)
Quite a common mix of these to get darks for example is Ultramarine Blue, a bit of Burnt Sienna or Burnt Umber and a tiny bit of Alizarin Crimson.
A good green (for grass or trees is made up of Cobalt Turquoise and Yellow Ochre).