This tutorial is great, as it combines alot of different Fill Pattern's together.
Phase One:
Press X then and then D on your Keyboard.
S1: You need to make a new image sized 6 pixels x 6 pixels with a tranparent backgound color. Zoom in all the way to 1600 and select the pencil tool.
With your pencil tool at size one pixel make this X:
Now go Edit>Define pattern.., name it "X" and press okay.
S2: Do the same as the last step but this time, make a line, like this:
Name it "line".
S3: Repeat step one once again, but draw a square, and name it "box".

S4: Do step one, once more, but this time draw a line round the edge, and name it "grid."

Phase Two:
Get your original image out (The one you want to apply this to). You
have defined all of the smaller images we made earlier, so, they will
be here: Edit> Fill> Custom Pattern.
Now go Edit>Fill> and choose the "line" one, set the opacity to
30%, press okay. Now do the same with "X", then with "Box", and last
but not least "Grid."
You should now have something like mine:

If not, don't worry, just keep on trying.





More Photoshop: