The paints I used for this painting are Burnt Umber, Yellow Ochre and Vermillion Red. Mixing Yellow Ochre and Vermillion Red results in a very intensive orange, and mixing Burnt Umber with Yellow Ochre results in a nice middle brown. I added the shadows in the branches by painting with pure Burnt Umber.
Besides learning about the various possible colour combinations I learnt that using a bigger format than the one I have been using might be appropriate. It is a difference whether you are using coloured pencils and markers or a paintbrush. The second thing I learnt is that it might be better to do a rough sketch on the acrylic paper to make sure that the composition is right.