Although a beadhead is a good choice i think. I'd use a clouser minnow , using basically the same countdown method AFish said , after you reach the depth retreive it with a slow , Slow , short strip. And if there are fish rising my goodness use a dry fly , try to see what they are eating and match it as close as you can with one of your flies , when trout are feeding on top in lakes they like to "cruise" around without using up much energy , like coasting slow on a bike , try to time your cast to the place you think the trout will coast to next. You might have to watch them awhile but that's cool too. If they are chasing flies that are moving around on top , do the same thing with your fly , skitter/skate/move it. HOPE YOU NAIL 'EM