Study your bizer map before going. Study it constantly. Look where you are staying, where you'll be going, and learn the hazzards and tricky spots you'll be facing. I bring it in the bathroom with me pre-vacation.
I wouldn't attempt any night boating until you know it like the back of your hand. I've been going up to Winni for a few years now and still won't venture out past 7:00 pm. I'm amazed at the folks who do go out at night, but I figure they live there and know it well.
You need your boating license in NH if you don't already have it. And if you do, go to this website and take the sample test a few times, just to be sure.
http://www.boat-ed.com/newhampshire/studyGuide/10103101
These are the things I do to get ready. I've destroyed a prop, going too fast in too shallow an area, that's about it thanfully. We've gone the opposite way with boats, selling our 20' Cuddy and just have a 17' aluminim bass tracker. We may rent a bigger boat, but still I need to know what the heck I'm doing at all times.