I'll definately second the idea of a practice head! When I first began doing face-ups, I bought one and it was a HUGE help!
Also...I think there most definately CAN be wrong ways to do face-ups. For example, if you are trying to get very fine, crisp intricate lines and are using pastels and pencils instead of properly thinned acrylic then, yes, you're 'doing it wrong.' Likewise, if you're trying to achieve a soft, blended look and are using ONLY acrylics then, yup, that's wrong. Because you'll never achieve what you're going for with the approach you're using, the approach is wrong.
As far as aesthetically wrong? Nope
Like everyone has said, beauty is in the eye of the beholder and if you love the way your doll's faceup looks and it's beautiful to you, then I don't see how it can be 'wrong!'