You all know the answer already, putting the starch on the back of the fabric. I use a 50/50 mix and if it really needs to be stiff for one reason or another I just increase the level of starch. One thing I didn't see mentioned was the method of application we use. My partner and I sell pre-washed kits. The kits are pre-cut as well using our accucut machines so we need the fabric stable to assure correct cuts. We use a garden sprayer, the kind with the pump handle. Works like a dream. You will have to remove the diffuser at the opening if you leave the starch in the sprayer and just use a pin to clean out the dried starch. Since we usually wash and iron 30 yards at a time, we also roll and plastic bag the pieces and put them in the freezer. In the refrigerator, if you get busy and don't get to them they will mildew.
Also for detailed info on using starch to applique. Visit You tube and watch the Sharon Schaumber videos. She is wonderful