The first, and most important, is a strong, shared commitment to welcome refugees into your community and to help them to build a new life alongside you. But experience of supporting refugees or other vulnerable people is necessary too, though you could acquire that through partnering with other organisations or groups in your area.
On top of that, members of your group will each have to be able to commit several hours every week to the sponsorship process, probably for at least 18 months, including preparing and applying to be a sponsor and providing at least 12 months of active support of the refugees when they arrive. Sponsorship is a voluntary activity not a full or part-time job, but it is not something you can take on (or drop) lightly. See Building A Group section HERE.