It's important to use a very sharp knife. Doesn't necessarily matter what kind (I use a large non serrated one, maybe 1.5 times the size of an average steak knife, for an easy grip and better control) but it has to be really, really sharp. I won't kill a bird with it until it shaves the hair off when I run up my forearm. Some people like to try and aim for the arteries individually but I don't see the point. Easier to botch if you don't know what to look for. I cut everything on the front and sides of the neck. Cut hard and fast. You'll probably have to saw back and forth once or twice, but done quickly this will only take a few seconds. The blood should begin to come out as a stream maybe a few millimeters thick. It's best to get both arteries but one will do. Even restrained in a cone birds tend to fling blood everywhere, so step back four or five feet to avoid getting it on you.