I use a long arched ramp and load and unload by myself. The truck is really pretty tall, so if you have a shorter truck a shorter ramp will work OK.
Finding a dip or a small hill helps tons. Get the tailgate as close (vertically) to the ground as possible. I use the crown of the road and the curb at my house to make loading and unloading pretty easy.
Another trick I use is to put the bike in gear. To unload I put the bike in gear and pull in the clutch. When I'm at the edge of the tailgate I let the clutch out so the bike stays in place, then I hop off the tailgate. Once I'm firmly on the ground I pull the clutch back in and guide the bike the rest of the way down. It takes some practice, but I don't have any trouble doing it.
In the truck I use soft ties girth hitched around the handle bars and some non-ratcheting tie down straps for the front of the bike. The bed of my truck is shorter than the bike, so I turn the bike to the side so that the tailgate can go up, then I pull the bike back so the rear tire wedges against the tailgate. This has proven a very sturdy way of transporting motorcycles. Between racing, working on bikes, helping out friends and whatnot I probably load a motorcycle into the back of my truck 50-60 times a year, and I use these methods every time.