It's the responsibility of all Catholics (priests, religious, deacons, and laity) to work to return Catholics to Mass on a weekly basis. Here are some tips for all of us to apply to our lives. The list is in no specific order.
1. Pray
2. Invite someone. If a new priest or deacon has arrived, seize the opportunity. If you are in the choir, ask someone to come hear you sing. There are plenty of reasons to invite someone. Just do it.
3. What do people always complain about? Homilies. When a priest/deacon gives a good one, tell him. Only tell him what he did well so he can mimic that. Never criticize, as that can come across as rude. Homilies shouldn't be too long, nor should they be light, unCatholic, or angry.
4. Encourage your organist to follow our Indexes Canticum. People hate bad music.
5. Have a neighborhood dinner with all the Catholics over and make sure the priest comes. Inform them that is a chance to speak to a priest in an informal setting. It's been known to work.
6. Try to informally find out what caused someone to stop going to Mass and work the issue through with them.
7. Similar to number 5, invite the entire parish to a meeting in the hall to discuss how to come back to the Church and to answer questions on the faith. This is slightly more formal than 5.
8. Have the parish do a mailing saying that those who have not been attending have been missed. (Some people would need to go through the parish listing and see who has not been there recently.)
9. Set up a diocesan outreach ministry for those wishing to come home. The Archdiocese of Philadelphia has a great one.
10. Tell someone close to you about what the Mass and the Eucharist mean to you. You know deep down inside you just have the urge to say to your best friend, "Ya know what I love about Mass?"
11. Send out a newsletter about parish activities.
12. Hand someone "The Mass Explained" by Fr. Larry Richards.
13. Invite someone to a diocesan men's/women's conference. Don't have one? Start one!
14. Get all Hellfire and brimstone and talk about our duty to God. (Not recommended often.)
Lastly, send these ideas to friends.