I'm with Lono, get as much training as you can. The more you know, the more clearly you'll think, both before and during anything that might arise. Scouts Canada offers lots of training throughout the year, and many leaders fail to take advantage of it. It can be daunting to give up family time to go to training but from first aid, to planning, to equipment, to training your youth, networking, etc... the payoff is worth it.
Beware that that confidence doesn't become complacence though. A lot of the horror stories we hear seem to stem from overconfidence, or an under appreciation for the risks. As for basic equipment, I'm sure to carry a cell phone, group-sized FAK, extra water, snacks, sheltering (i.e. blanket, tarp, etc.) and paperwork, regardless of what we're doing. In the summer I add a kid-sized hat, sunscreen and bug spray to my must carry list, and in the winter I add kid-sized hats, mitts and socks.
We also have group supplies, like whistle lanyards for everyone, and a group equipment backpack. We could probably spend hours talking about all the bits and pieces...
Training and preparation, added to our detailed trip plans and excellent communication, a attention to the weather forecast, make me much more confident taking the man-child and his peers out for adventures.