I attend a church which has about 100 children each Sunday morning and 50 teenagers each Sunday evening. What you need is a core group of families willing to commit to the church, some family-friendly activities and time. Basically if a church has lots of children and youth, it attracts children and youth and it's self-perpetuating to some extent. My kids go to see their friends as well as enjoying most of the activities.
It's easier to keep children/youth in the church than bring them in later in life, so focus on young families first. During the week, we run a pre-school (with paid staff), we have a weekly toddler group and a weekly "messy church" style group, and we run a bible study group for mums with young children (ie come and study the bible whilst your children play around you or constantly interrupt you). On Sundays, we have creche for 0-3s and "Sunday school" for 4-11s, then youth group in the evening. We run events such as a holiday club, youth socials; we run courses (eg bereavement, divorce, depression, parenting, Alpha). But to do all this, as well as lots of volunteers, we employ a youth worker, children's worker and families worker.
Assuming you only have volunteers, then I'd say see if you can run a messy church once a month, a toddler group weekly if possible and a youth group once a month, and maybe an occasional parenting course - you can basically use a video course then just discuss as a group. Invite your friends and encourage other members to do the same (or invite neighbours, grandchildren, etc). Be welcoming to those that come to those activities and signpost other things going on. Chat to the attendees and individually say "why don't you come to X?" as people are much more likely to come then. Make the services welcoming to children, eg make it clear that you don't mind if the children don't sit still or make a noise, and have at least one simple song that children can relate to or do actions to.