This is a really good question, and there are many fine answers to this question.
I think one of the best places for someone to find information on sponsorship is in the text of the Big Book as it relates to step 12. There is a lot of information about how to approach a newcomer-- show that person how you solved the drink problem, etc. When I went through the steps the first time, someone told me to turn all that information around as if I were the person seeking help. As it was explained to me, the information in "Working With Others" is not just what I want to bring to someone seeking a solution, but what I want to find in other people in the program as I continue my spiritual journey.
On a personal level, I tell my sponsees several things before we go through the steps. These things are just what I found to be helpful. They are not intended to persuade anyone or tell someone that the way they do things is wrong and my way is right. They are only my own practices based on my work in AA.
First, I tell them that I am only a transmitter of the information in the big book as it relates to the steps. That is what my purpose is in their life. We will likely get to know each other on a very personal level in the course of the work. However, that does not mean we are going to become best friends or go everywhere and do everything together. I prefer to think of myself as a step-guide who has found a solution by working the steps of the program, and I am passing on the solution I found in the Big Book as presented by my step guide(s).
Second, the first step tells me that my life is unmanageable, and that no human power can solve my alcoholism. For these two reasons, I can neither cure someone of alcoholism nor manage their life for them (I cannot even manage my own). Therefore, I can only show them what I did to recover from alcoholism. I cannot advise them on what job to take, give relationship, medical, or legal advice, or tell them how to spend their money.
Third, as regards the steps: I show them only what I did that removed my desire for and obsession with alcohol. To do this, I go line by line with them through the Big Book, and do everything it says the first 100 did. If it says to pause and ask ourselves something, that's what I do. If it says we write on pen and paper, I write with pen and paper. When it comes to the 10th and 11th steps, there are very specific instructions on how to do them, but there is also room for discovery of one's own truth about how to approach the practices they describe.
The most important thing I have found in sponsorship is that I have to allow room in the process for two things. One of those things is for the person I am working with to have the dignity of their own experience with the steps. The other is the spiritual experience that the steps are intended to produce. I was allowed the dignity of finding my own truths through the work that my step guide(s) did with me when they took me through the steps. As a result, I had what I believe to be a powerful experience with the steps. This is a process in which one is searching for and making contact with their Higher Power. It is not a process in which I am teaching someone my way of how not to be an alcoholic. I try to have a light touch and make sure there is room for a Higher Power to enter into the experience, since that is the only power that can relieve me of my alcoholism.
Finally, on sponsors as people. . . I have learned a few things in my short time in AA. My sponsor says things like "I expect you to. . ." and "you need to. . ." and there are times it rubs me the wrong way. I don't like to be told what to do, especially in a way that makes me feel as though my sponsor is above me. In the years that we have had this relationship, however, I have found it to be true that I have had an effect on him in a similar way that he has had an effect on me as it relates to our recovery and how we work the program and carry the message. We have both had a spiritual experience as we have worked together. However, as a sponsor myself, sometimes if I catch myself directing someone how to do something "right", I realize it is because I am afraid that I am going to fail at helping them. I know what worked for me, so it is easy for me to say that is exactly what someone else must do. Thanks to the 10th step, I realize that I must watch for this behavior, ask at once for it to be removed, and turn my thoughts to someone I can help.
Again, these are just thoughts based on my own experience, as it relates to my journey through the steps and as an alcoholic in AA. Thank you for allowing me to share with you all.