@ Bushi - I have that book - I LOVE that book! Great resource!

@ Fran:
a - Practice practice practice!
b - I've looked into that and still can't figure out (meaning I don't think it's possible) how to add a multiple layer file to a multiple layer file without pulling each layer over to the next document one by one and lining them up. Can't figure out how to merge them.
c - The order is determined by what you wanna SEE. Think of it this way - as you look at the layer stack and your resulting image - realize you are looking at the layers from the top down. Whatever is on a layer (we'll call it #1) above another (call it #2) will overlap on TOP of that layer - whatever is on #1 will cover up whatever is directly below on layer #2. If you wanna see #2 covering #1 - move #2 up above #1 in the Layer Stack.
d - In the Layer Pallette - at the top right of the stack is a property labelled "Opacity" - with a numeric indicator that by default is set to 100%. Change it to 50% and it becomes HALF transparent - get it?

  Sounds like you may be rushing things too fast without learning more of the ins and outs of the program - you are seeming to want to do all the high-end stuff from the start and it does takes some practice and getting used to.

  As far as what will raise and lower the bumps - whatever is 128 value grey will not produce a bump. Anything lighter (129-255) will produce a bump, and anything below (127-0) will produce a "dig" meaning it will appear to be below the surface.

  And don't be afraid to use photos of rust you can take with a digital camera - or buy collections from the likes of Dosch or 3DTotal, and mess with them in PS. You don't HAVE to hand draw natural elements in order for it to be something of your own.
  And it doesn't even have to be rust - it can be side tread of a worn tire - you can take the pattern or scuffing and color it to look like rust in another image - get the idea?

  I'll say it again - practice practice practice! This won't come overnight - you'll have a LOT of frustration if you're expecting high end results fairly soon out of the gate.
  Hope that helps-
-Lew ;-)