Make sure your wheels are on properly.
Rear wheel just dropped off my inlines and acted like an anchor. Splat.
It was weird. I could feel my boot just dig in and I actually had time to run through multiple scenarios of how best to break my fall before hitting the deck. I opted for a drop to the knees (no pads) and fall foward on to forearms.
I was very impressed with the controlled landing, and then suitably embarressed by it being obvious i'd not checked my wheels before skating.