One of Wolfgang's favorite sayings, especially when things got frustrating, was "From nothing comes nothing." Wolfgang was the only trainer I've ever met who never lost sight of the true goal of most dressage riders: to move up the levels. In every horse, he would quickly spot the more advanced movements that came easily to that horse, and he'd go ahead and have the rider school those movements, even if that rider was at only training level. For example, when I was an utter newbie, my horse was a lovely Swedish warmblood mare who had a perfect canter, naturally balanced and adjustable. When Wolfgang came for a clinic, he'd have me school collected canter, counter canter, and flying changes, even though I was barely training level. Of course, we also schooled lots of training level. But he saw no reason not to let me get the feel of more advanced movements on things my mare could do easily. And no, I didn't do them perfectly. You have to crawl before you can walk.
Put another way: Wolfgang believed in using the advanced movements to improve both horse and rider. He wasn't one to keep you on a twenty-meter trot circle until you could do it perfectly. He viewed that as boring the horse into submission, and he always wanted a little fire, a little expression. His exercises often tended to be aimed at moving the horse's shoulder and/or haunches around--basically a second- to third-level skill. He didn't care where the horse's head was on the first attempt, as long as those haunches moved over. From nothing comes nothing. It's not going to look great at first, but that's ok. Remember your equitation, give it a try, and praise praise praise any attempt the horse makes.
From nothing comes nothing. It's a call to ride out of your comfort zone--not all the time, but often. Don't stay stuck at training level for years. Try out some more advanced stuff, and then return to what your horse knows well to instill confidence. Don't expect perfection -- don't be afraid to fail -- and improvement will come!