Simple Paul Klee method using oil paint and watercolour
This is a very easy technique to follow and it can produce some interesting results with a little practice. The oil paint lines that are created by transfer of paint on stretched string build up the composition and allow for easy application of the watercolour. Build up layers of different colours and highlight shapes formed by the grid of lines.
The demo shown here is an improvised example but you could try copying some of Paul Klee's work or draw the composition before application of the oil paint. Don't aim for perfection, it is the little flaws and smudges that make this technique so interesting.