We have Welcomers on the door at each service. As well as give out order of service etc., their job is to try to spot new people and help them if they need it.
We cover some of the all age services (so family services) as Welcomers and we always try to get children involved in the collection. If we spot children we don't know we'll ask their parents if they'd like to join in- it breaks the ice without being OTT.
The vicar always gets all the children to come up the front when he does his talk - he normally makes it fun for the kids. We've had an adult lying down in the front of the church whilst the kids measured them as part of one talk and they made porridge during another talk (that got a wee bit messy but who cares - the kids enjoyed it and we all had a laugh at our lovely vicar covered in porridge!
Our vicar always has children doing the readings at the all age services. Parents love to see their children taking part and it's a good way of starting a conversation afterwards by saying how well their kids did.
Young children have an area at the back of the church with puzzles and colouring books so parents can sit with them there if they're getting a bit bored (our all age service only lasts 45 minutes but that's ages when you're three!)
We also have tea and coffee after every service at the back of the church and the vicar encourages people to stay for it.
We even invite tourists to join us. We're in a tourist town so we have people who come along to our church to have a look around and if it's after a Sunday service they'll often hover at the door as they see people milling about having coffee and biscuits and the kids running about. So we ask if they'd like to pop in for a coffee! Most don't but still have a look around the church which is nice.
Last Christmas we had standing room only in the Church - 300 people plus. It was lovely.