1. make sure your inside pedal is at the 12 o' clock position and keep your weight balanced between your outside pedal and inside hand (so turning left - keep your weight balanced between your left hand and right foot). Don't be afraid to lean into the turn.
2. support your upper body on your hoods - only your legs should be moving. you can also 'rock' back and forth for more leverage (i.e. pull to the left when pushing down on right pedal)