The best advice I ever got when I began applique work was "practice, practice, practice". I would also suggest you watch others who do it and go to as many classes you can. I pick up a little pointer from almost everyone I watch. Do you use freezer paper templates? That is how I do all of my work. I put it on the underside of the fabric and needle turn around the sharp edge of the paper. Then before I finish the piece I pull the paper out with forceps (therefore not comprimising the integrity of the back with cut holes).