Flare smoothly at 17ft, simultaneously closing the thrust levers at to be at idle by 5ft.
If you underflare - ouch! Delay reducing thrust - don't pull back excessively as you are just rotating the wheels into the ground (think C of G and where the main wheels are) and flare a bit higher next time!
If you overflare, relax the back pressure and drop the into wind wing.
If you flare correctly (ie you are about 10cm above the ground) relax the back pressure / ease forward very slightly and you won't feel the wheels touch.
+1. That's my winning technique as well.