I think that Beech leaves make interesting subjects. Prominent veining, convoluted curves, long pointed buds, and little designs on the branches. I had a lot of fun with this one.
I tried to work wider and smoother tonalities and got a bit of that here, although the veins are somewhat harsh. What I think I missed was the overall sense of shadowing. I have read that it is important to not get mired in detail until things are roughed in. I think that first dropping in overall shapes and shadows will help.