Hello.
First thing you want to gather photo references.
As you can see, your tree isn't really close to real pine trees.
You need to reproduce better the height, the colors, the silhouette, the details.
I did a quick edit, I'll show you how to go from this to this :
I don't say my tree is perfect, but it's much more recognizable and realistic in my opinion.
Look at how the lighting is richer simply by putting the sun on the left and sticking to it
with consistency.
COLORS :Change the color palette. When I checked all your green, they were all from the same hue :
Remember that sun light is warm, whereas shadows are rather influenced by the sky reflection, which is blue and colder. So make sure you have different hues for each value of the lighting of your objects. This technique is called hue shifting. This make a huge difference. You can also use this as a stylistic choice, aside from just replicating the reality. You can make a purple shadow and a blue highlight for example ?
NOISE :Also, you added too many lonely pixels, that's why your tree feels noisy instead of textured. Try to gather pixels together so they makes small lines / patterns rather than being alone and separated. Another very important point is the rendering of the branches, they must absolutely give this 3D feel otherwise it looks flat and weird. To do so, simply add shadows under each branch. Draw a bright branch (the part which receive the light) and just under it, draw a darker line. This way, you will feel much more the volume of your tree.
I hope it helps. Anyway, you should really try to improve your workflow : a solid workflow will greatly reduce the amount of mistakes you make.
