Ok to start off I got 1000 and 2000 grit sandpaper, blue painter's tape, blue & black vinyl paint, primer, and clear coat from Autozone. (I used Duplicolor but I know a lot of people use Krylon too.) You'll also need an X-Acto knife which you can get from any hobby store.
Now to paint the case-
1.Sand the whole case with 1000 grit sandpaper.
2.Apply a light/medium coat of primer.
3.Wait about 45 minutes, and if it needs another coat of primer, apply it. Otherwise, spray on a light coat of blue.
4.Sand the blue with 1000 grit sandpaper.
5.Apply another medium coat of blue. Wait for ~45 minutes again.
6.Sand the whole case with 2000 grit sandpaper.
NOTE: You will not have to sand any more after this! If you do so, it might ruin your controller.
7.Put on the third coat of blue.
Now you have the base coat, blue.
8.Take out your painter's tape and cut a piece off. Maybe ~ 10in.
9.Put the tape on a cutting board or other hard surface; using an X-acto knife, cut a design out of the tape. This will be one stripe in the design. Make as many stripes as you plan on using.
10.Put the tape on your controller, making SURE you have the tape firmly on the plastic.
12.Paint the controller again with a coat of BLACK this time. Make sure the first coat is very light.
13.After applying about 3 coats of black carefully take off the tape.
14.Put one or two clear coats on the whole thing and then you're done!