At my very first retreat I sat next to a woman who was working on a beautiful hand-appliqued piece. I stopped and just watched her for several minutes, then started asking questions. She was more than happy to explain and demonstrate her technique, which was the freezer-paper-and-starch method. I practiced this method for a while, then moved to using Templar heat-resistant plastic and starch.
I suggest trying different techniques until you find the one that clicks for you, then practice it.
Also - IMO, Yoko Saito is a master at hand applique. I took a class from her in Houston several years ago, she showed us (among other techniques) how she makes super skinny hand-appliqued vines. I tried her technique and holy cow, I can make beautiful vines and anything else skinny, as narrow as 1/8th of an inch. There are several videos of her on YouTube, I highly recommend you check them out.