Just did my first tig welds today and I have two questions.
First, what's a good rule of thumb for stick out?
Second, is it a good practice to drag the cup as you weld or should I try and hold it up off the workpiece as I weld?
Thanks

Stick out is pretty relative to cup size... if your just using the collet body diffuser that come with most machines starter kit your stick out should be pretty short. This make seeing what your welding a bit difficult. Using a gas lens allows for longer stick out and the really big cups allow for ridiculous long stick out.

And unless your walking the cup, I try to not let it touch the metal. You can scrap the still hot weld and leave undesirable scratches on the weld.

Piggy backing on JD here...

my rule of thumb for standard cups is no more than the inside diameter. so for a #7 cup that would be 7/16" or less.
As far as minimum stickout, it needs to be at least far enough to see the tip. Like JD said, using a gas lens lets you extend tungsten further and that can make things easier to see without getting a crick in your neck.

Hi James
if you drag the torch along the workpiece whilst welding it basically forces you to hold a strongly sloped torch angle. This can contribute to problems with arc stability, gas coverage and balling up of filler material, especially if you are welding with a dab & move technique as opposed to laywire.
The importance of a steep torch angle becomes most apparent when welding on AC so it's even more important if you intend to weld aluminium.
It can be nice to lean the cup against the workpiece whilst fusion tacking but not recommendable for actual welding in my opinion in most cases.

By the way, when you say dragging I presume you mean pushing. So your torch travels in the direction of the gas flow, i.e. from right to left if you are holding the torch in your right hand. That's an important one too just in case you didn't know. Welding backwards definitely not recommendable unless you have limited options