That 8x10/360mm is a very good combination for LF portraiture. As to overall technique, I think the best way to get the portrait you want with that camera is to get a rapport going with your subject. Talk to them for a few minutes before putting them in front of the camera, so that they're relaxed and ready to shoot. Give them a little advance prep as to what to expect, so they understand what "sit still" REALLY means.
Originally Posted by jnanian
John, You have it!!
Let's face it (pun intended), a portrait that speaks beyond words is one that captured the right expression on the subjects face, usually. You must be ready when you see it and it rarely happens by chance.
With children I still have them say "cheeeese", (unless they insist on not being happy) it always works and holds their attention long enough to get the shot, but with adults I usually instruct them to look down - sometimes I offer/suggest a thought - and when they feel relaxed or ready, to look up at me or at the camera. So, yes, it's mostly about the eyes ("windows to the soul").