Lots of good advice here. One thing that really helps me on any trail, is I usually run tail gunner. Now most folks don't want that position, so I take it. I get to watch everyone else (and their mistakes) when going over the different obstacles. I get to see first what works and what doesn't. On the toughest obstacles I have a fantastic spotter (Larry Hull). I trust him. He gets me over things that look like a no go.
Over the years (my first trail was Chinamans way back in 2000) I have learned what each of my vechicles can do and how they react. My Ranger does different than my Explorer and the Samurai is a total different beast all together. I have wheeled all of them during the different stages of up-grading and my driving style has changed with that as well.
Like has been said already, get out on some of the easiest trails and see what you can and can't do, getting in with this group is a great place for people that are willing to help you learn you and your trucks capabilities, ALWAYS GO WITH SOMEONE. Never go alone. The more you go, the more comfortable you will feel. Confidence is a major part of your driving as well. Heck, I still get butterflies on some obstacles (part of the thrill I guess).
Hang in there, it will come. Just don't try to do too much before you or your rig is ready. That will turn you off wheeling faster than anything.