First off, I gotta say this is a very nice piece already. I like the foreground trees, the midground is pretty good as well. I like the colors you've used, I think it works pretty well together. Reminds me greatly of a place I know about 75 miles north of me in God's Country. It's my favorite part of the state!
As nice as it is, I think there are a couple of areas you could work on.
I think it kind of suffers in the composition a bit. My eye isn't drawn to the foreground trees, they're drawn to a spot on the background mountain.
I find this spot competes with the foreground trees. This competition of one to the other I think is too strong and so gives you two competing subjects.
For example, if I cut out the top half of the picture, you have a stronger composition.
Now the trees in the foreground are the subject for sure. There isn't any competition in the background and your eye can meander through the rest of the painting.
Something else I see is almost two separate paintings which really don't relate to one another... the hills in the background, and all of the interest in the foreground.
Above the red line you see one type of painting, below the red line you see another.
Moving some of the colors from the foreground into the hills (mountains) in the background will help to connect them (the colors will need to be muted).
The other main thing I'm seeing is very little eye path or a circuit for your eye to follow. For example in the lower half of the painting, there are two horizontals bracketing the main midground, so you have no reason to travel into the deep background. Introducing some movement upwards will help. I would suggest lightening the foreground/midground, add bits of interest as you move the eye up into the trees, swing the eye across and up into the hills and let it escape through the top of the painting. I would also lighten some of the more distant fields with the light breaking between the trunks a bit. Consider highlighting one tree in the midground opposite the foreground grouping to help draw the eye across the midline of the paintng. A few highlights on the leaves and a few lighter portions of the limbs in the sunlight will help to lighten the heaviness of the treeline. Below is a possible workup on these suggestions.
Really though, I think another problem is the most distant mountain. If you were to remove part of it and change it into an interesting sky, you could really add some snap to this painting by drawing the eye to different parts of the painting. Lowering the chroma saturation of the sky from a powerful blue to a more less powerful blue, adding the smallest bit of burnt sienna, a touch of red, or yellow ochre to the clouds closest to the horizon will add to a feeling of distance to those clouds, and then make them more blue white as the clouds move more overhead. Making an interesting sweep across the whole of the sky rather than puffy whites will allow you to make the eye be drawn around by differing weights in the sky. The sky will be the lightest portions of the painting, since that is where the light is coming from.
Lowering the hills will help to keep the focus on the ground, and the opposing lines in the hills and sky allow your eye to explore all the great color you've placed in there already.
This is only one of many possible workups on this.
The main hint I have with acrylics is to use a extender medium for glazes, and also use a retarder to give your paint enough open time for you to blend it the way you want. You've done such a great job already on your blending, I thought you'd used oil paint. I really, really, really like the subdued colors on the mountains in the background. The grayed reds are just delicious. The colors in the foreground are pretty nice too.
Keep up the good work!