You have a great start! Now go and read some more tutorials

. Here are some things you should concentrate on:
Lighting - The signature has no real light source. If you look, the lighting is coming from the the upper left side of the render. Here is a very simple method to create a lighting effect. Create a new layer, fill with black, take a white brush (100-200px) and brush where the light source should be (upper left in this case). Set this layer to linear dodge.
Blending - The render is not too well blended in this case. If you look at it, it looks like it is floating on top of the signature, not in the actual environment. This is due to poor blending. This can be fixed by softening the edges of the render w/ a soft brush eraser (don't do this too much... I mean the VERY edges). After the signature is assembled, you want to add some photofilters and gradient maps (black and white on luminosity and a color one set to soft light or color w/ lowered opacity). This will give the signature a more unified feel.
Depth - This is, obviously, how three dimensional your signature looks. You know how when you look at things far away, they are blurry and when you look at things up close, you see a sharper, clearer image? Well, do the same to the signature. Objects (like your render) that are up close, sharpen a little and objects farther away (like your background) blur. Blur/sharpen according to depth in, so objects in between the render and background will be more less sharp than the render but sharper than the background.
Flow - This is the general direction the eye wants to move across the signature. It's sort of the direction which the signature moves. You should determine this direction and then build up effects going in the same direction.
Text - I'm not one to be speaking on this subject, but try to keep it close to the focal so it doesn't draw attention away from it. Also, depending on the style, try to make it small and not so noticeable

Enjoy, have fun, and good luck with graphics.
PS. Either put the render behind the border, or loose the border completely.
This post was edited by SaffasMissionary on Aug 22 2008 08:31am