It looks good for a first time, but try and add some more effects into it, work a bit more on the render + text. Like somebody said earlier, maybe add a border to it, to draw attention away from the cut edges.
Its great for a first, most people's first's has too much for the eyes in it, but this ones too big, and the entire time i was loading the page the picture showed up little by little and i was expecting some uh, pizzaz lol... But like i said, great for a first one GJ
Good signature dimensions are 400x125 thats a pretty standard signature, now for the border. To make a border select the "Rectangular Marquee tool" below the move tool, now click and drag what ever size you want it, just don't make it to big or it will draw attention from the actual picture. After you get your size it'll be a blinking dotted line, now simple create a new layer and fill it in with black or w/e color you want, then duplicate layer and move to opposite side of image. Hope this helps, Rep me if it does?