Here is my first real tutorial.
You start out with a black document. I'm using 380x140.

Then grab some really nice brushes, and brushes all over the document using white. Here is what I have so far:

Now take out a render that you like and place it wherever on your sig.

Duplicate your render once, then hide the original render. (Press the eye next to the render layer) Go to Filter>Liquify and liquify the duplicated layer. Then set it to Overlay.

Duplicate the Liquified layer about 4 times, and move the render so it's covering up the whole entire sig. (Make sure they are all set to Overlay)

Put the original render to the top so its the first layer, and duplicate, Set the mode for that duplicated render to Overlay. That should give the render better lighting. Add some text and a border.

Now, press ctrl A, the whole sig should be selected. Then press ctrl Shift C to copy the whole entire sig, now press ctrl V to paste it. There should be a new layer at the top of the 'layer list'. Set it to Overlay and then go to Filter>Blur>Gaussian Blur and set it to about 2.0.
Here is my final result:

Be creative, just mess around with it.

Its my first tutorial and I'm really bad at gfx but I just want to see what I can improve on.