Many Spiderman tags lately. Anyways this one looks pretty good, only some smudge parts look oversharpened.
I think a small lightsource above his head would make the sig a little better. Other than that, it's a lovely sig
Good but not tut worthy IMO. The text needs work and the focal isn't too great either. and that too. Nice work, just try to correct those things.
Is this really the first siggy you've ever seen? Ummm... this is pretty much exactly how every signature using that stock/render turns out. I'd suggest you work on the things listed above, and your colouring.
The top lighting would look better just white because thats the color of the light thats hitting his suit