Apply a bit of layer effects:
- Inner glow (white, opacity = overlay 50%)
- Drop shadow (black, overlay 20-30%)

Duplicate the layer, send it backward the layers palette (behind the original green layer), change its color to darker green (almost black), and move the shape itself a bit down - it will give leaf some depth.

Select green layer with leaf again, then make new layer above it, and Create Clipping Mask (from Layer menu, or Ctrl-Shift-G). Use large soft Brush tool (B) with white (and then black) colors to add highlights and shadows to the leaf.

Set this layer opacity to Overlay, 30-40%

Then create another new layer, fill it with grey, and apply a lot of Noise (Filters menu).

Create Clipping Mask for this layer too (Ctrl-Shift-G), so that this layer is also masked by leaf shape. Then, find Smudge tool (hit Shift-R until you see the finger icon), open Brush settings dropdown, select 4th brush from the end of default brushes set, set Strengh to about 50%.

with short mouse movements, smugde the noise in the direction of leaf growth.

Do not stop until all noise is smudged :-)

Finally, set this layer opacity to Overlay 40-50%