When you find your ball under the lip of a bunker, the instinct is to try and help it up in the air.
Unfortunately, this often creates the opposite effect – a thin strike which hits the lip and falls back into the bunker.
Instead, setup with the ball slightly forward in your stance and open the clubface slightly. When you make your swing, feel the club pulling through towards your left pocket with speed. This will force the club down into the sand and cuts under the ball – popping it up quickly.