the shades of greens are to close together. i like the monochrome color theme, but you shuold have changed the contrast to make it look less blegh and plain. that and add a little more depth to the effects you use.
Make a signature without those silly lines. They don't blend at all and they become the focal point of every single signature you're posted. These monochromatic coloring jobs don't do much for you either. Look up some effects and coloring tutorials.
It has a nice design and layout but the color is what's ruining it for me. A rule I use is to never actually change the color of the render used. I use the colors from that to make a background. Try a "Curves" layer to heighten some color in it. Add a deeper effect with the brushes. Maybe use them to make a drop shadow? Good job, though.
