Once you catch the rope, flip on your back - head facing the sky and tuck the free end of the rope over the shoulder opposite to the rescuer. This establishes an automatic ferrying position. You can use the top part of your arm to add a bit of friction if necessary. Hold on with both hands and pay close attention to anything the rescuer tells you to do. Keep your elbows tucked in on top of your belly, loose elbows can get banged up on rocks. Remember your defensive swimming skills, keep your feet on the surface of the water to bounce off any obstructions downstream. Avoid grabbing the throw bag or end of the line, you want to be in the middle of the rope. Never place your hand inside the end loop (I would avoid even placing fingers there as well). This is why we retie the ends with small knots to avoid such temptation. Don't wrap the rope around your hand either as it makes it harder to let go quickly and you may accidentally pull your shoulder out of joint.