In watercolour, the water plays a greater role than in other water-based media (like gouache or acrylic). The water is not only the solvent but influences the quality of the colour and the final effect and is therefore an integral part of the aesthetics.
With watercolour, you can let the water do the work (or at least some of it).
The following method was shown to me by a watercolour tutor years ago:
1) Draw lightly with a pencil on a dry watercolour paper the form you want to fill with colours;
2) Take a clean brush and load it with water;
3) “Paint” the whole form with the clean water;
4) Take some colour from your palette with a round brush;
5) Touch the centre of the form with the tip of the brush and see the colour spread and fill-in the form.
This technique works better if your watercolour pad is slightly tilted (30 degrees approximately) because it help the pigments go down. This technique is good for intricate forms, in particular if you want to have a smooth wash like in the wet on wet technique.