As far as new member assimilation goes, I think the best way is to invite the new person to participate in whatever charity work sessions that you have regularly. We put that info in the new member packet, plus make personal invitation. The new member may not want to work in that group forever, but there is time and opportunity to visit and get to know people.
Another effective thing to do is to introduce new members to other new members or members who have been there a few months. They will confide in each other and not feel stupid asking each other about things they don't understand or just heard, but have no clue about.