The pilot reported that he was practicing touch and go maneuvers in the airport traffic pattern. During his second approach to land, the pilot improperly selected his touchdown point at the beginning of the runway instead of the runway threshold. When the pilot recognized he was not on the runway glide path by looking at the “visual approach slope indicator lights” (airport has a precision approach path indicator), he increased power to arrest his descent rate, but the right main landing gear collided with a road sign at the north end of the runway before the displaced threshold. The airplane impacted the ground, nosed over and came to rest inverted on the runway, and the airplane sustained substantial damage to the left wing. The pilot reported no preimpact mechanical malfunctions and anomalies that could have precluded normal operation.