It can be a really good idea to make a hatched drawing, moving the pencil quickly in one direction, pressing harder for a darker tone and applying less pressure for a lighter tone.
At the art academy in Belgium, we made hundreds of these type of drawings using plasters as our reference. I would go into college in the evening and sit in front of various classical busts, using just line to portray tone. It was a great way to learn how to look, establish tone and suggest light.Such a classical training has been a wonderful advantage to my paintings.
These type of drawings can then lend themselves to simple watercolour studies. Using a very limited palette, I look at the tonal blocks and quickly, I place the colour onto the dry paper using my Classic brush, well loaded with paint. I invite some colours to merge into others leaving tiny little dry sections which act as barriers, trapping the paint on either side and suggesting light. Its all done in one stage, in one go. Yes, I know it seems scary, but its really fun.
This is painted as one shape. I know your probably thinking its more than one shape, but actually all the little blocks of colour are linked, they all touch.
I begin with the girls head working down the body and arms, then the legs and whilst its all still wet I attach the pram. Its really important that the shape remains wet, otherwise it looks as if the pram is not attached to the girl. I add the shadow last, hoping that some of the shoes and the pram wheels are still a little damp so that the colour seeps a little into the shadow.
When you are learning to paint, you can be taught various techniques, but learning to look is the most important skill you can aquire. The subjects we choose to paint are also important, you really have to want to paint them, they have to inspire you.