Turn any photo into a dot grid artwork with these Photoshop actions. You'll get great results with dots that change size. They get larger in brighter areas and smaller in darker areas. Free download available.
I added a couple of color spots with the brush tool.
Add the below pattern from auto shapes palette. Modify it.
Add some lines using the Line Tool. Maintain the 45 degree angle.
Finally add Title. That's pretty much it. Press Ctrl+0 and take a sight at the design. Should you feel anything needs a change or to be added feel free to do it, and try to be creative.