"Kevin" wrote: (clip) Do you first round off a part of the leg, apply the
rest, round some more, and move the rest down to the newly rounded bit?
^^^^^^^^^^^^^^
That's one way you could proceed, but it may not be the best. Putting the
work into a steady-rest before it's running true will force it to vibrate,
so it may never true up. The long spindle will start out thicker than it's
going to end up, so it will vibrate less. The smart thing is to get a
smooth round surface near the middle for the steady rest early on.

If you start to have vibration before the piece is round and smooth in the
middle, it is usually possible to reduce the speed to get away from any
resonance. Then, gently wrap the fingers of your left hand (if you're right
handed) around the work to support it. This will damp the vibration and
also keep the wood from bowing. The soft, half-open grip of your hand will
allow the wood to find its own center (hopefully.)