The technique that I find so beautiful about oil painting has a name, imagine that! Its called Impasto, the texture you can see and feel with your fingers from the build up of paint on a canvas.
I have also learned the technique of Fat Over Lean. Your background layers of paint need to be very thin and top layers thicker. Otherwise, your colors will all mix together into mush.
In this painting, I made the warm background with very thin layers of paint and the tree in the foreground with thick layers. The blue flowers are very thick blobs of paint which make them pop off the paper.