Svend, yes, thanks for the reminder about hands. That was the biggest difference initially. How you handled the front of the bike is quite different between road bikes/mountain bikes. NO PULLING UP on hills with MB's! Or an unwelcome wheelie is in store! 
L.
Lynn, when climbing, you want to have light hands so that the front wheel can deflect a little bit and "flex" with rough terrain -- up/down and side to side (a little bit). If you keep your arms, wrists, shoulders rigid, then the wheel will tend to bounce off of rock/roots/ruts and you will have a tough time of it. And tire yourself out in the process. Relax, go with the flow, adjust steering and path as needed, but with finesse, not brute force. And by all means keep your weight over the front. Or put another way, keep your C-O-G vertically over the crank or slightly ahead. No wheelies! Fore-aft balance is key.
Despite your full suspension rig, you still have to use your body as a shock absorber and let the bike move underneath you to flow over the terrain. Elbows, shoulders especially, but also knees and hips -- always keep 'em loose and moving to absorb bumps and depressions, etc. Get yer butt off the seat too, when the terrain demands it -- ie. super bumpy, steep descents -- and give the rear wheel some more freedom to move up and down and smooth out the trail if needed, and get your C-O-G back when going downhill.
Have you and Jim played with the suspension settings on your forks and shocks? Rebound adjust? Air pressures? Travel adjust? I assume so, knowing Jim's attention to technical details. But if not, this is well worth tinkering with, and can really improve your steering control on rough trails.
Hope this helps....
Svend