This past weekend, my family had the opportunity to visit two churches that we do not regularly attend. On Saturday, we attended my niece's first communion mass and on Sunday visited a church where an old family friend was guest-preaching.
In both cases, we were warmly greeted at the door and warmly greeted by those sitting around us, some of which were curious about what brought us there that day.
There is a mountain of research advising churches on how to treat first-time guests with the goal of return attendance: be welcoming, be curious but not overwhelming, and make it easy to follow up. There is also a mountain of research advising fundraisers on how to treat first-time donors with the goal of a second gift: be thankful, communicate the impact of the gift, and start a dialogue.