Informal events work, too, like game nights, potlucks. One church has discussion circles right after the coffee hour, but newcomers may feel shut out. Designate a leader to invite newcomers into the discussion and give background. Ask visitors to help, so they don't feel shut out by the leadership. Ask newcomers to read the Church On Loan material, for example.
Some churches assign a mentor to each new person.
Religious Education RE for both children and adults is important. Teachers and organizers burn out. Or have teams teach, so that teachers take turns and have a chance to attend Sunday services. Tape services or have written copies for RE teachers who hate to miss the service. RE teachers can feel isolated because they don't attend Sunday services from the adults.