My method is a lot like Jerry's, but a little different so I thought I would mention it too.
I drive a Suburban, and I like to keep my little feet dry too! :D
After getting everything else ready to go, I let out five feet of slack winch strap, leave it hooked to the boat, and make sure to "re-engage" the winch before backing down the ramp.
I ease the boat into the water slowly, until it floats off the trailer and pulls the slack out of the winch strap. Then I ease forward until the nose of the boat settles in the middle of the bunks, and becomes slightly stable while the rest of the boat floats. (I have side guide-bunks also)
I walk back to the left rear tire of the Suburban which is on dry ground, step up on the tire with my left foot as I grab the luggage rack with my left hand, step onto the bumper with my right foot while holding the luggage rack with both hands, two step shuffle to the right, then I step down onto the boat trailer just behind the hitch. Unhook the strap, then step into the nose of the boat, start the motor and pull over to the dock.
In the winter time I usually just let out more slack because the water is shallower around the ramp. Then I use the strap to steady myself in between the truck and the boat, much like a high wire act at the circus, as I make a perilous descent on a narrow, yet slippery trailer beam above the icy cold water. It is at that precise moment, sometime next winter, I will wake up for a second, and wonder......... Why don't I just do "the smart thing" and install a walkway platform like my buddy Jerry did???
"I'll see you at the lake!"
Mike Simpson