I'm new at this too...went balls deep on my first real boat. The boat was slipped at a marina in a channel with slips down both sides...channel is 40 feet wide, boat is 35 feet long. Marina is located in a channel between 2 lakes so we have currents and wind influencing what the boat will do aside of the size of boat. To add to the mix my props are set spinning in...using forward reverse has little effect on maneuverability. Slow...go slow...have help on board and hopefully the other marina users are like the ones at mine...a boat comes in, everyone jumps up to help out. 3 years and 80k later resurrecting this boat...my first time going into the slip I was terrified. Have dock lines and a dock pole ready...you'll need these less and less as you get more experience...oh and big a$$ed fenders/bumpers. I picture the events in my mind before attempting them...go through the sequences mentally .. seems easier that way. Then just do it. The first time the bow got caught by the wind coming out of the slip and swung the wrong way...well I won't get into that story now...but I haven't hit anything yet. Once clear of the marina...play with it...as often and in as many varied conditions that you can...seat time seat time seat time.

All great advice, but seriously rent a smaller boat a few times before shoving off in your monster to practice the above techniques and to learn the basics of how a boat's handling are affected by wind, current, forward/reverse selection and prop angle. Operate it around the ramp and practice docking, trailering if possible.

It's very evident the only requirement is some states is a 10 minute class, or in Florida zilch if you're above a certain age. Lunacy, considering people can't even operate a vehicle with traction (automobile) within lane lines, between curbs, with a plethora of signage etc. yet throw them in a boat without any knowledge and its fine.

I would enroll in J. Darr's off shore driving experience.........

Pete hit the nail on the head. Visualize what moves you are going to make before you make them.