Do a church-wide push for people to serve one time during Christmas services, events, programs, etc. Usually it is counterproductive to get up in front of the church and ask for volunteers...especially if it comes across as "begging." But it can be effective at Christmas if done correctly.
The Pastor should be the one who makes the ask during a church service. He should share about the opportunity the church has to reach many people for Christ during the Christmas season since people are more likely to be thinking about "religious things" and attending church. New people will be walking in the doors of your church and people who aren't currently serving can step up and serve one time at Christmas and have a part in seeing people come to Christ.
Have a list of one-time serving opportunities that are available during Christmas. The Pastor should ask people to commit right then and there to serve one time. They can indicate on a provided card what area(s) they are interested in helping with and then turn in the response card.
Make sure the people who signed up to serve one time have a great serving experience. Place them in an easy role. Give them clear instructions about what they should do. Pair them up with experienced volunteers. Have snacks and food for them.
After their one time serve, connect back with them and invite them to join your volunteer team on a full-time basis. If you will be intentional about doing this within a week after they serve, you will see many of them join your team. I have seen as high as 85% of one-time volunteers join our volunteer team on a full-time basis when we did this.
Ask your current volunteers to invite one person to serve with them during the Christmas season. If you will be intentional about encouraging your volunteers to bring someone to serve with them, you will see many respond and do so.
Encourage it. Have each volunteer write down the name of one person they can invite.
Promote it. Create a theme you use to build momentum and create a culture of reproducing yourself in others.
Pray for it. Pray during the weeks leading up to Christmas that God would send new volunteers to join the team. Ask your volunteers to join you in praying for this.
Honor those who bring someone to serve. Celebrate the stories of volunteers who impact others by getting them involved in serving.
Your volunteers know people you don't know. They have influence with people that you don't have influence with. You can only invite so many people to join the team by yourself. But when your volunteers also begin bringing people to serve, you will see your volunteer team begin to grow exponentially.
Partner with student ministry. Christmas is a great time to involve students in serving. Not only can you enlist them through the first step mentioned, but you can also go to the student ministry and invite them directly.
Talk with the student ministry pastor/director at your church and ask him/her to help you enlist students to serve. Students often have extra time since they are out of school for the holidays and can make a big impact if you'll give them the opportunity.
I trust this post has given you some fresh ideas and inspiration to build your volunteer team this Christmas. If you will build your volunteer team during the Christmas season, you can enter the new year with momentum, energy and excitement.
You can get more proven ideas for building your volunteer team in my book "The Formula for Building Great Volunteer Teams." It is available at this link.