what type of acrylic paint should I use ??

  You don't need to use  the fancy kind. Any kind of acrylic paint will work even the normal craft kind It basically dose the same thing. But you need to remember that you have to put a top coat  on or it will chip. It is better than trying 2 do your design with nail polish and its cheeper. I recomend buying a long thin paint brush. A long brush helps with control and the thinness helps with the detail.