First plug it in, and let it warm up for at least 1/2 hour..
(just kidding) I bump the pan when trickling, and try to time the swings until I know I'm really close. My personal theory is that it takes a little bump to break the magnetic hold on the beam. I've trickled powder so slowly that my Hornady scale didn't register the change at first, then shot over my target weight. Really, as long as you end up at the weight you want, it doesn't matter how you do it.