Before your appointment, try to avoid any caffeine like coffee or tea, it tends to make your eyelids "jittery" and it affects the quality of your set. Come in without any eye makeup to speed up the prep time. Exercising before an appointment also helps with being able to lay still and relax.
If you want to wear liner, liquid is the way to go! I recommend Stila or Kat Von D, they're faves of mine.
Absolutely not. A bonding agent exclusively used for eyelash extensions may be purchased after your appointment that is extension friendly.
Moisturizing your face is totally okay, keep sunscreens and eye creams away from your eyes and especially your lashes.
As a notorious face sleeper, I can tell you from first hand experience that my lashes lasted much longer when I started sleeping on my back.
Or as long as you possibly can. It's like when you've just painted your nails and it's dry, but it hasn't set yet. The same thing happens with your lashes, let the glue completely dry and set before getting them wet!