Remember that just because you pray for a missionary experience, doesn’t mean it will happen immediately. Praying for something won’t do much if you aren’t working hard to get the results you’re praying for. Be friendly and when the opportunity arises, invite them to come to church.
Have a “bring a friend” night at mutual where each girl brings a friend, and everyone plays getting to know you games. They might be turned off if you invite them to a very spiritual activity at first where they can’t participate, but if you do something they’re familiar with at an activity, they’ll have a better experience and be more likely to return.
One of the responsibilities of a class presidency is to minister the the less-active members of your class. Spend a Sunday evening visiting with the less-active members of the class and let them know about upcoming activities they might be interested in.
If you have more ideas or a personal experience you want to share, send them to firstname.lastname@example.org