Well, some things that are practiced at the Seminary/Abbey where I study include:
-Always dress modestly (no shorts, tank tops, flip flops, hats) while inside the church.
-Genuflect before the Blessed Sacrament, if reposed in the tabernacle, genuflect with your
right knee touching the ground reverently. If exposed, kneel on
both knees and give a bow of the head before standing up and moving on.
-Keep custody of your eyes. Never look around distractedly, but always focus your attention to the priest, reader, or Jesus on the altar. (some notable instances in which you should keep extra-careful custody of the eyes include people coming in late for Mass, children running around or crying during Mass, EMHC’s coming up to the altar, other people receiving Communion)
-Keep good, straight posture. If possible, try not to use your hands as support on the pews in front of you. If you want, you can fold your hand if it helps.
-When using a hymnal or prayer book while standing up, always hold your book up to chest level and also avoid looking around when using the book, but keep attention to the words on the prayer book.
-When receiving Communion, try not to look at the EMHC/Priest/Deacon distributing the Communion but rather focus your gaze on the Host that he presents before you.
-Use the postures specified in the Missal, like striking your breast thrice at the “through my fault, through my fault, through my most grievous fault” in the Confiteor,
bowing (kneeling on Christmas and the Annunciation) during the Creed (whether it be the Nicene or Apostles’ Creed) when it mentions the Incarnation and Birth of Christ (in the Nicene Creed, “and by the Holy Spirit, was incarnate by the Virgin Mary, and became Man” and in the Apostles’ Creed “who was conceived by the Holy Spirit and born of the Virgin Mary”),
bowing your head towards the Host before communicating (try to do it as if you were bowing to the person in front of you receiving Communion. That way the Communion line runs more smoothly, and
only giving the Sign of Peace to those nearest to you (don’t go walking up and down the aisles giving the Sign of Peace to everyone you see, nor should you awkwardly reach out your hand to someone 2 pews away. It’s really distracting to others

)
-If you want, you can bow your head (and not chest) at the name of Jesus. (Note: it is only done at the name Jesus and not at the other names for Our Lord)
-Kneel down before Mass, to ask Jesus to give you the proper disposition for receiving Him lovingly and after Mass for a short time just to thank Jesus, for receiving Him.
Well, there are probably a lot more, but that’s all I can think of at the moment!
God bless,
Facite