Start From The Beginning
Any techs knows that PDR is a highly visual art. Most good techs have trained their eyes to see the small subtleties in the reflection, and are easily able to see their tool tip in any size, type, or depth of dent long before they make an over push. The bottom of the dent or crease should appear clear, very detailed, and show you exactly where to make every push. If you need to over push the bottom of your dent to see your tip, that may just be the first sign that something is wrong. The most common problems are: