The pilot reported that during the takeoff roll from a soft field turf runway, "I was not as aggressive as he should have been." He reported that the airspeed increased, the airplane began to rotate, but without enough airspeed to sustain climbing flight. He reported that he "pushed the nose over", the airplane settled to the runway and bounced. The airplane overran the end of the runway, struck a fence and sustained substantial damage to both wings. The pilot reported that there were no mechanical failures or anomalies with airframe, flight controls or the engine that would have prevented normal flight operations. According to the manufacturer pilot operating handbook, for Soft-Field Take-off: Hold full back pressure as you taxi and as the takeoff roll is begun. If the surface is marginal or too narrow for gradual turn on to the runway, align the airplane with the runway, apply full brakes, and build up takeoff RPM before starting the takeoff roll. As you apply full power, move the control wheel to neutral and allow the airplane to accelerate to 65-70 MPH. Lift off with a light back pressure. After lift-off release enough of this back pressure to permit the airplane to accelerate to its best angle- or rate of climb speed as required by obstructions.