I think this lives up to the headline. I've made some progress in my parish through much infighting: Jubilate Deo ordinary, congregational introits, no more Glory & Praise music, psalms at communion and chanted propers. But many of those tasks can seem insurmountable to the beginner on the road to reform. So let me offer one of the changes I made which is so simple but goes so far in fixing up the liturgy:

Ditch the "Great Amen".

It's so very simple. Nothing in the GIRM, rubrics, or tradition (that I know of) requires the congregation to sing "Amen" more than once at any point in the Mass. Yet today every Catholic pewsitter knows that the IMPORTANT part of the Mass ISN'T the words "This is My Body" but when you have four chords and sing "A-A-MEN, A-A-MEN, A-A-A-MENNNN" and then repeat it. I've even heard catechists say that THAT is the point where the bread becomes the Body. Oh, and the scores for these "Great Amens" always have FFF as the closing dynamic. This HORRIBLY imbalances the Mass!

So when your priest sings "Through him, with him, in him" to the simple tone, just respond on the same note he used as the reciting tone: "Amen." If he uses the solemn tone (with the slurs on some syllables), respond according to the pitch he ends on "A-me-" and then move up a whole tone "-en." It's all so simple, no one can object to it if it's done routinely, and it makes SUCH a difference in how the Mass is perceived by the congregation.

I'd add as well that there's some sense in using the "Great Amen" for a festal Mass, say Easter. I've even used them with the Latin Canon. But as a general practice, a chanted "Amen." puts the emphasis BACK on the Eucharistic Prayer rather than on the response to it, as it should be.

Getting rid of the bombastic Memorial Acclamation is quite a bit trickier, but the "Amen" at least gives you some inroads into reforming other parts of your music at Mass.