At low altitude engine loss you have no choice but to land straight ahead. Anything but the slightest heading adjustments will most probably end catastrofically. Your memory items are (at least, depends on complexity of aircraft):
Gently but decisevily lower the nose
Close fuel valve
Adjust airspeed for landing
Flare and land
How do you determine if you have enough runway ahead? That's a tricky one, and in this situation you quite possibly have milliseconds to make that determination. It's going to be an estimate at best because you certainly wont have time to do any calculations. As a general rule I'd say if you have around half the runway length left you're probably good.