I am sponsoring a couple of guys in AA and have found Hamilton B's book 'Twelve Step Sponsorship: How It Works' very helpful. He has some useful suggestions for sponsors:
A sponsor's main role is to help the sponsee work through the 12 Steps.
A sponsor can help give newcomers guidance, encouragement and an explanation of what AA is about.
A sponsor can help answer questions about recovery
A sponsor is helpful in the self-examination process that the Steps require.
A sponsor reminds a sponsee to follow the 12-step principles in their lives
A sponsor shares his own experience, strength and hope
A sponsor can monitor progress, confronting when it is appropriate, and generally help us stay on the recovery path.
A sponsor encourages the sponsee to read the Big Book and other AA literature
A sponsor helps the sponsee build healthy relationships.
A sponsor is available during times of crisis.
A sponsor cannot keep a sponsee sober.
A sponsor is not a therapist
A sponsor should never take advantage of a sponsee, attempt to control his life or encourage an unhealthy dependence.