I'll throw something I did for the first couple of weeks....
Hold the throttle and the bar end at the same time. Not only is it easier to keep a steady speed in the begining but it also slows down the turning of the throttle.
I would keep my pinky and ring finger both gripping the bar end with the rest of my hand on throttle. Then moved to just the pinky, within two weeks of getting the bike my control of the throttle had vastly increased. Sometimes on bumpy roads and very long rides I still grip the bar end and use it like a cruise control/throttle lock.