Locodave
I launch a 6.2 m fiberglass half cab often on my own. As said in other replys it really depends on your trailer set up. Like musty said if your trailer allows it you should be able to drive your boat straight up to the front roller on your trailer, leave your motor in forward gear with enough revs to hold it there while you go and latch it up at the winch, Go back to your controls turn motor off, tilt motor up, then pull pull the boat out. Most new fiberglass boats are set up to be put on this way. Now if you drive your boat on your trailer you can drive your boat off the trailer aswell, on your own too. So, back the boat down the ramp and into the water as normal. Jump into the boat over the bow, start motor and put in forward gear with enough revs to hold it there. jump back out to the winch and un-hook the hook,jump back in the boat and put into neutral, the boat should start to roll/float off trailer, as you knock it into neutral and start moving backwards i always start to lift the motor with the trim button. Tie to warf or pull up to bank and go park your car.
Trailers
As said most trailers for new fiberglass boats are set up to launch and retrieve in this way. Most new boat/trailer set ups these days are also set up in the way that if your boat and trailer is on the ramp and you undo the hook at the front your boat WILL roll off the trailer. This is why it is necessary to have the motor in forward gear while un hooking and hooking the winch cable up. For this reason i never undo the safety chain at the winch until the boat is in the water and never pull the boat out without having the safety chain attached.
You might find that when you un hook your boat at the winch it may sit there and not roll off. This is ok, you can use a bit of reverse to drive the boat off the trailer.
Alot of people use this method of launch and retrieve but have one person in the boat and one person driving the car and working the winch. but no reason you cant do it alone. i do it alot.
Go to some good fishing ground boat ramps such as. Shellharbour, Kiama,Port Kembla, or for syd silverwater cooks river. and you will see alot of peaple using this method and see how its done. And go with a mate for the first few trips to try it with some help.
Too long ? Sorry Dave