Yes, it’s true that every Friday used to be a day to abstain from meat.
Women covering heads was required.
Parishes used to have 40 hours devotion before the Blessed Sacrament.
May crownings of the Virgin Mary were done by most parishes, although you’ll still find a few that do it now.
There were 4 mandatory ember days per year with fasting and partial abstinence.
Outside processions were commonly done for the feast of Corpus Christi, although some parishes are getting back to that now.
Parishes commonly had a mission priest come in and do a retreat during Lent and/or Advent, whereas now, many parishes don’t have anything like this.
The fast before communion, which had been 3 hours, was reduced to 1 hour by Pope Paul VI.
There was a white cloth attached to communion rails that the altar boys would flip over to cover the rails before started to kneel at the rails to receive. After everyone received, they would flip it back over.
Of course there are the more obvious things like Mass not facing the people back then, no communion in the hand, no altar girls or women readers, Mass in latin, choirs were in the choir loft and not in front of the church.
I’m sure there may be other things - this is just what I remember right now.