Stop gripping those watercolor brushes so tightly. Loosen your grip, actually try to paint while holding your brush further up the handle. Keep your fingers off of the metal ferrule.
In sample 1, 2 and 3, the tree, grass and flower are painted with a tightly held and controlled brush. Often times, painting like this causes the strokes to become very uniform and rigid.
In samples 4, 5 and 6, the tree, grass and flowers are painted with a very loosely held brush. The hand is not resting on the table top. Use your arm a bit more and not just the hand. The strokes are freer and looser. The outcome is a more relaxed, carefree and emotional painting.
A bonus to this more expressive style would be the bristles will last longer and maybe your hand will not cramp up as well. Loosen up your grip on your brushes to create more expressive and free flowing watercolors.