This critique is done by
Since you are interested in learning to paint trees, let's focus on that first. Two important things that I like about your main tree is that you have created a good silhouette shape for the tree. This is very important. Second, when I look closely, I see that you have varied the greens and do have some warm colors mixed into the tree foliage color. If you want increase the color variation a bit more, Burnt Sienna is a great color to mix into green foliage to create color variation.
The main improvement to the painting would be to increase the feeling of light and shadow. First ask yourself, 'Which direction is the light coming from?' Let's say, above and from the left, which means more light on the left side and on the top of the tree.
Subdivide the tree foliage into two parts, light foliage and shadow foliage. Pick a general value for each area. The shadow area might be a dark value; the light area might be a middle value. Keep the subdivision simple. Don't break the tree into too many parts. Paint the shadow piece or pieces first--all at one time. As you paint, hold the value to dark and vary the color randomly as you go. You will be creating an overall shadow shape which has a distinct leafy edge. Let this dry.
Now paint the lighter part of the tree. The light foliage will be warmer with more yellow in the green mix. A good yellow is Raw Sienna or Quinacridone Gold. As you fill in the light side, remember to hold to middle value and randomly vary the color mix as you go. Wa-Lah! You now have a three dimensional tree with a distinct light source.
Two other quick suggestions, let the shadow side (right side) of the house be a darker overall value than the left side. Also, gradate the foreground. Let the foreground be a darker middle value at the bottom and gradually let it lighten as it goes up toward the house. This will give the foreground depth.
I have attached one of my watercolor paintings as an example, using the ideas discussed here. For more ideas please go to my web site and check out the watercolor videos. I plan to have a new video on landscape available late in 2009.
Keep painting and have fun!
Additional note from the captain - Take a look at the colors within Ken's foliage. That's what makes him a master.
I took Nancy's painting and punched up the shadows of the house using photoshop.
Often, intensifying the values makes a huge difference.
No guts, No glory.
Finally; This is what a scissors will do for it., but that's my style, not necessarily what you should be doing.