An addition/amendment to Dave's most excellent writings.
As I extend my legs while transitioning onto the wire I don't slip the mainsheet through my hand. The concept here is that the main is trimmed for you being onboard and as your weight is moving out you are auto-trimming for the new balance. And I think the tight Mainsheet works to close a stability triangle. IE the third leg of a stool.
My other change is that while coming in off the wire (this is for a tack) I grab the handle briefly to raise myself so that I come in on both feet. Not standing up but in a rolling motion so that I end up in the middle of the boat, on my knees. While this is happening, the helm is being pushed over and the main is being eased. What I'm trying to describe is a tack started from the wire. If you are coming in because the wind dropped than land on your bum as Dave described. But, if you are tacking, skip the bum landing and go straight to being on your knees moving across the boat.