Mass of tree foliage too flat and uninteresting
You have just painted a mass of tree foliage but have just discovered it looks like one big flat shape. If the paint is still wet just use your fingernail or the rounded edge of and old credit card and scrape in some branch shapes. This breaks up the tree shape into more interesting ones.
If the foliage mass has dried too much. Wait till it is thoroughly dry, then glaze over it with clean water. Wait 30 seconds for the water to be absorbed by the paint underneath and then scrape in your branch shapes. Remember, to create interesting shapes avoid regular even branches which divide a shape into equal parts. Irregular sized shapes and angles make for a more interesting composition.
Areas of you painting look disjointed i.e. too many small unconnected shapes.
Connect these together with a strong wash of watercolor paint.
Tone too light in a section of your watercolor painting
This is an easy one to fix.
All you need is a glaze of watercolor over the area that is too light and it will quickly repair the light area.
A small section of your painting is too dark
Again you can use the same technique for removing an object only just use it long enough to lighten the shape you want to adjust.
Lost all highlights in my watercolor painting
If you want to reclaim some lost highlights you can either do this with some judicious use of Chinese white or white gouache. In small areas this does not detract from the overall transparency of your watercolor painting.
If you want to reclaim more white you can try using some find sand paper, I have used this to create the impression of foam on waves. This technique can only be used as a last resort however as once you have done it you cannot paint over it as the sand paper removes the sizing.
Continue to: Muddy watercolor and problems with design