What you'll need:
A Jet Ski on a trailer
Access to a Dock to load the Jet Ski into the water
A car or truck or something capable of towing the trailer (with and without the Jet Ski on it)
And, of course, a Life Jacket
Step 1: Personal Flotation Device
Grab a life jacket before getting on or even looking at the Jet Ski. The water doesn't care how good of a swimmer you are; under the deceptively pleasant surface of the water it is harboring a deep grudge against you for leaving it to walk on land.
Water will kill you. And it won't even send flowers to your funeral afterward.
So grab a life jacket, one of those ones that you can strap yourself into. Chances are if you get thrown from the Jet Ski you won't be in the proper state of mind to swim.
Water, she be a fickle mistress. Much like gravity.
Step 2: Equipment Check
Before doing anything with the Jet Ski you must check to make sure that you have the proper equipment on your Jet Ski. A small Fire Extinguisher should be located in an easy to find panel and you should always check that it is there before starting your Jet Ski. You wouldn't want to have your engine on fire when you are surrounded by water.
Make sure that the safety strap is attached to the kill switch on the Jet Ski. Most
Also check and make sure all of the straps, the one on the front that holds the Jet Ski on and any other additional straps, are secure and tight. You wouldn't want to lose the Jet Ski on the way to the water.
Step 3: Driving to the Dock
These seems like an obvious step but I'm putting it in here as a word of warning.
Drive there, don't try to walk it there.
The reason for this gets more obvious later.