Try this:
When about 100ft AGL, flare the helicopter without raising the collective, that will decrease the speed and the rate of descent. When you have about 30-20 knots airspeed, level out and slowly raise the collective until you touch the ground. When sliding forward on the ground, keep the collective up until it has stopped.
Autorotations is hard to get the hand of and it is varying with different helicopters. But when you get the hang of it, you can practically do anything to get to your landingspot, you can go sideways, backwards, 360 turn etc. Just keep the rotor RPM in range and your landingspot in sight. :)