Keep the sun to your back. This brings out the color of the balloons and maximizes the available light for slower speed films. It also prevents lens flare, which is caused by direct sunlight on the lens. Look for odd or unique angles. Every shot doesn't have to be at eye level.
Nothing is more spectacular that witnessing dozens of balloons ascending at once.
That certainly calls for a wide angle or panoramic shot. Keep both hands on the camera and your elbows to your side. Slowly exhale and begin squeezing the button. Jerking or punching the shutter button may cause blurring. In composing your pictures, remember the rule of thirds.