For people like myself with long limbs this is always a difficult and generally not a very pretty technique!! Here is a great tutorial on how to improve your technique, required at red tag grading.
Notice the kicking leg coming up straight at the beginning of the delivery with the foot chambered in a backward position, then with the rotation of the opposite knee outwards affecting the angle of the pelvis whilst in the air the kicking leg is brought into an elliptical trajectory and then the foot is deployed at the end of the complex. This I believe is the key to delivering this technique effectively; it stops you swinging a big long lever round to the target which puts a lot of pressure through the hips and back.