4 

Now we need to add some depth to our texture so it doesn't look too flat. Firstly, go ahead and copy your layer. With Layer 1 Duplicate active go to Filter>Stylize>Emboss. Set Height to 3 and Amount to 90%, click OK.

5 

Set your Layer 1 Duplicate mode to Overlay and then add Noise by going to Filter>Noise>Add Noise, use about 8% for the amount and check guassian and monochramic boxes. Click OK.

6 

If you want light up your texture a little bit, then make a new layer and use big, soft airbrush to paint over your texture in some spots. When done painting set your painting layer mode to Overlay. Before making a new pattern we need to flatten our image (make it all on one layer) so go to Layer>Flatten Image..to make it one layer.

Finally, save your custom pattern by going to Edit>Define Pattern, name it "Rusty". Your custom rusty pattern is now complete! Move on to the next step to make a layer style out of it.