That just means you suck at aiming and position. The method is perfect, the execution is vital, especially when you're fighting stuff that can kill you very quickly.

You just have to get a feel for how far away you can be, taking into consideration your latency. If you've got good latency one day and perfect the method, but the next day you have ~500ms higher latency, your whole method just got Fed in the A. Best I can say is:

Practice
Make sure you have imp CoC, extended range, permafrost, aim with your mouse(if you right click to move your character around, CoC will always shoot directly forward of your camera,) and make sure you do not have frostbite.

You also have to keep in mind that some monsters SEEM to have a farther range than others, I don't know if they do or not, but for example, the crocs in ZG seem to have a normal range, but the tigers seem to be able to attack from farther away. This is just a visual thing, you can HIT them from farther away too, it's very similar to the druid in catform thing, how their range seems screwy.