I've done it enough times that I now have the lines hooked up at the plane and rolled out, then pick up one line at the handle end and pull, if the elvator goes down - I put that line down on the ground again.
I pull the other line- if the elevator goes up I hook that to the up side of the handle.
Then I pick up the other line and hook it to the down side of the handle.
After both are hooked up I look at the handle, make sure UP is on top in my hand, give full up and look at the elevator-make sure it is up, then full down- check elevator - deflected down; only then do I check / adjust for neutral.
And I have still managed to pick up the handle upside down, but not since I put safety thongs on the bottom!