Basically all you need is:
-a pair of white or blank canvas shoes (you can get these for really cheap at a lot of discount stores)
-dye in blue and pink (I used some out of a tie dye kit)
-white acrylic paint
To start off, soak the shoes (and the shoelaces) in some water. Then begin sponging on pink and blue wherever you'd like. Just go crazy with it! You can sponge on some water over the top to sort of make the dyes swirl around a bit. Once you're done adding colour, flick or dot white acrylic paint on to make stars.
That's it! (Let them dry, of course!)