Cover your canvas or panel with collage paper. I recommend sticking them down with matte gel medium and sealing them with another layer.
Start adding to the background with paint.
Continue adding to the background.
Continue developing the background. Start thinking about the composition, keep it light where you will want to put your design elements (face, boat or anything else you might add in your painting)
Sketch in the face. I also put in a 'river' to break up the background and avoid it being too samey.
Develop the face sketch further.
Start painting the face with a base colour and some initial shading.
Develop the shading. This process can take quite a few layers. Build up layers of translucent paint by adding matte medium to your paint. Dry in between layers.
Don't be afraid to go quite dark with the shadows and light with the highlights on the face. It adds depth and interest.
Fold a paper boat and adhere it to the painting with plenty of gel medium. Paint a sail.
Add music notes to the hair with a white paint pen.
Have a good look at your painting and see whether everything fits together. Pay attention to how the background works together with the foreground, whether the contrast in the whole painting makes sense. Make adjustments with paint and glazes until the painting feels right.