First make a new image, I made mine 500x500px.
Now press D to reset the swatches to it's default color.
Now apply a Clouds filter by going to Filters > Render > Clouds.
Next go to Filter > Distort > Glass and use these settings:
Now go to Image > Adjustments > Levels and increase the contrast so that it will look something like this.
After that go to Filter > Brush Strokes > Accented Edges and use these settings
Go to Filter > Brush Strokes > Angled Strokes now and use these settings:
Next go to Filter > Stylize > Find Edges.
And finally, go to Filter > Blur > Gaussian Blur with a setting between 1 and 2.
This is what I got with the above steps.
Click to enlarge
