I have finished the sand base colour next the bit I am not looking forward to the green and brown splodges. I have done a practice and what seems to work for me is paint the shape with a normal brush then go over the shape with a cut down brush held vertical stippling to break up the edge of the paint.
I might well be in a rubber room at the funny farm by the time I finish.
Made a start. I think I will try and keep the painting sessions short so I can stand back and make sure I am keeping my splodges toughly the right size.