There are many different ways. I use the chopping block and ax, but I grew up using an ax so I am comfortable with one in my hand. If you are not comfortable with an ax, a hatchet will work also and is easier to handle. You can use a killing cone (do a search on this site) put their heads under a broom handle and jerk, or use other methods.
The best way to me is the one that you are most comfortable that you can be quick and sure. It does get easier with time, not so much that you get hardened to it as that you get more confident in your ability to do it and do it right. To me it is not so much which method, but being quick and sure in how you do it.