It is important to adopt an optimal and consistent "working style" with our ballheads, or any other photography equipment for that matter. The following description is one working mode that we can recommend for the BH-55 model. Of course, you can adapt this to suit your own style.
Orient the Ballhead
Rotate the body of the BH-55 ballhead so that the drop notch closest to the Main Locking Knob is on the left side (at 9:00 o'clock if you are looking top-down) and the other drop notch is at the front away from you (at 12:00 o'clock). This places the Main Locking Knob conveniently for you to operate with your left hand (at about 7:00 o'clock) while your right hand is free to operate the camera controls. With this orientation, you can readily tilt the camera body over from horizontal to vertical using the drop notch.
Orient the Quick Release Clamp
The optimum orientation for the Quick Release Clamp depends on the camera gear and the clamp style.
Screw Knob Quick Release Clamps: Put the clamp's knob facing front, toward the subject. This places that knob underneath the lens. If you're mounting a lens, then orient the quick-release clamp with its knob pointing to the right. This helps avoid inadvertently releasing the camera gear from the clamp by confusing the quick release knob with the main locking knob which is operated with the left hand.
Lever Release Quick Release Clamps: Conveniently orient the lever either towards the front or the rear, left or right, without worry of interference. This is possible because the lever does not protrude more than 5/8" when closed. Little worry of "knob confusion" in the heat of battle!
Adjust the Drag Set
Some photographers prefer to have tension (drag) on the ball at all times to prevent the camera from suddenly flopping when the main lock knob is loosened. If the drag is set with enough tension, you can position the camera and lens at various angles and if you release the camera it will stay in place without needing to fully tighten the Main Locking Knob prior to exposing the shot. The optimal amount of drag depends on the size and shape of equipment being used as well as the angles at which you wish to place the equipment. Heavier, larger equipment and steeper angles require a higher drag setting. There are two ways to set the drag:
One, with the Main Locking Knob loose, set the drag using only the Drag Set Knob; or,
Tighten the Main Locking Knob and then tighten the Drag Set Knob just until you feel the screwing resistance change.
As you adapt a fixed procedure that works for you, it's best to practice that working mode on a consistent basis till it becomes second nature. This will save you time in the field and help avoid costly mistakes. Seasoned pros are able to setup and shoot literally within seconds. Happy Shooting!