I also use a very fine needle to do any work where I want my stitches hidden. It can sometimes be a challenge to get it threaded but worth the effort because the end result is nearly invisible stitches because you can pick up just a thread or two of the fabric with it. I also try to run needle and thread inside along the fold of the applique and bring my needle out right at the fold and then catch the base fabric a little under the fold of the applique piece. This also really helps hide the stitches. Batik I've found really varies in stiffness and the stiffer the fabric the more challenging it is to get it to fold the way you want it to especially on curves and points.