Hagbah is mostly about form. Grasp the etzei hayyim firmly. Then pull the sefer slightly off the desk. Keep your back straight and bend your knees as you raise the sefer to a vertical position. Then straighten your knees and turn around so everyone can see the print. If you are strong enough, straighten your arms as much as you can to raise the Torah high. Look at the pictures in Donin's "To Pray as a Jew" to learn. And always always have someone spot you.