This actually started with questions from a new bird owner who posted his questions in the sticky " How to Teach your bird to step up and to come out of cage" the OP is MrCavyMadness. I put this information so that everyone can refer to it from its beginning, but please answer it here.
I do not pick any bird up by its neck as it is very fragile and I would not risk doing the bird harm in this manner.
In answer to how to go about taming your new cockatiel, I think that Pajarita did a fairly good explaination of what you need to do. But lets go into it a little more. The main thing at this point is just to spend a lot of time talking to your bird from outside of its cage and offering it an occasional treat such as spray millet to begin with. No putting your hands into the cage except to provide food and water and maid service( cleaning). The first 30 days or so are rather stressful to the bird as it is all new and unfamiliar to the bird. This is a dangerous situation to find yourself in even with the support of your flock and pretty much a death sentence if you are a lone bird. This is why your bird is afraid and reluctant to come to you. Talking to it will help to reassure it and I think that for the most part this birds nature is such that it will almost tame itself if you will follow these suggestions and allow the bird the opportunity to see that you mean it no harm.