I always try to take balance into consideration where I insert flowers into the arrangement. I know the lilies will open to a large flower head, so I want a large flower on the opposite side to balance out the look.
You can see by the red line the amount I will remove with a sharp cut of my florist knife.
A side view shows the natural rounded curve I've trying to achieve with the flower arrangement.
You can see while the rounded look is being achieved, you'll also notice that the leaves are above the water line.