One of the things you learn in learning to design professionally is that often how you frame the problem is as important as trying to solve the problem. Case in point. And lest anyone think this is a strictly Catholic problem.
What am I saying? I'm saying that framing the problem as "how can we grow the Church?" is doing it wrong, that framing it as "what can we do to keep people from leaving" is doing it wrong, and that examining polls about what people think about the Church and using that to inform what we do is doing it wrong.
What do you get when you frame it this way? You get anxious wringing of hands. You get "programs" and "initiatives." You get more fish fries, carnivals, spaghetti dinners, and pancake breakfasts. You get a watering down of doctrine on both faith and morals, homilies that are nothing more than banal, earthy moralisms. You get artificial attempts at being hip and relevant that those who are hip find repulsive and irrelevant. In short, you get everything but the Gospel.
So how should we frame the problem? The answer is in the name of the popular term "new evangelization." No, it's not the "new" part ("renewed" would be more apropos in this context); it's the "evangelization" part. The way to frame the problem is "how can we best share the Good News?"
And the answer is the same today as it was for the Apostles. First, we must ourselves repent and believe. Second, avail ourselves of the sacraments. Third, go out into all the world. In other words, authentically follow Christ and show others how to do the same.
Parishes should be focusing on how they can best celebrate the sacraments. Parish priests should ask themselves, "How can I celebrate the Eucharist fully faithfully, authentically, in the richest way possible?" The answer is not to get creative or worry about incorporating pop music or other profane activities (I'm looking at you, Austria). On the contrary, work to restore a sense of the sacred, transcendent, otherness; treat it as if we were truly encountering God because, ya know, we are. Foster Eucharistic Adoration.
Ask, "How can I make confession more convenient for my parishioners?" Show them how important it is by making it a crucial, daily part of parish life, not a Saturday afterthought. If you're in the confessional and nobody comes--that's okay. Take that time to pray. It's a win either way, but people will come.
Ask, "How can I teach the faith more authentically in my homilies?" Preaching should challenge people to grow in the faith, not be complacent in it. It should equip parishioners to direct their own lives towards God and also to be able to explain it to others. It's okay if they don't get it all right away.
Ask, "How can I ensure parishioners are prepared for the other sacraments?" Marriage--be strict; be faithful. Don't smooth over the harder teachings; you're not doing anybody any favors by doing that. Baptism--teach what baptism really is all about; reinforce how important it is to do it ASAP, not when Aunt Bertha can make it in six months later. Ditch the feel-good 80s infomovies. First communion and confirmation: for the love of all that is holy, make religious education free. And on that subject, make sure your teachers are orthodox. Challenge the kids, too. Again, it's okay if they don't get it all right away--mystery is a good thing. Treat these things seriously, like they are real means of grace and not social events.
People--complacent, lukewarm people--are going to be bothered by this. "But Father..." will be heard a lot. People may even threaten to leave. And then do it. That's OK. They did that to Jesus as well. The Gospel is not a popularity contest. It is not a way to reassure everyone that they're okay and good being however they want to be. It is demanding. It is the narrow way.
So all these suggestions are related to steps one and two--getting the house in order. Out of this will grow, quite naturally and authentically, evangelism, that is, the apostolate of the laity. Educate the laity in their responsibility for evangelization; think about how to better equip them (e.g., apologetics courses, Bible studies, and evangelism practice) and support them in it.
I'm not saying that priests don't think about these things. I'm not pretending any of this is novel (quite the contrary). But there does seem to be a kind of forgetting, or maybe a thinking as if this is somehow not enough. And so the focus shifts off the essentials and onto all these other attempts at "keeping" people and "growing" the church, instead of keeping a firm hold on Christ and growing the faith.
I think most priests know they need to do this, but they're held back. Maybe they're afraid of offending their parishioners. Maybe they recognize what a sea change in parish culture this would be. Maybe they're just intimidated by the effort it implies. That's why those of us parishioners who understand this is the way things need to be should encourage and support our pastors in these efforts. But it needs doing regardless.