When whipping cream the cream should be as cold as possible, and the bowl should also be very cold. The cream will whip easier and to a higher volume when very cold. (A very slight pinch of salt added at the beginning also helps the cream to whip). When the cream is about 1/2 whipped, add the sugar and vanilla and continue to whip. If you add the sugar and vanilla at the beginning, the cream will not whip to high volume.