Dipping your fingers in holy water on the way in.
Touch the water in the font at the entrance and make the sign of the cross with it.
Do it deliberately, and say to yourself: I was baptized.
The fonts are emptied during the Triduum. That absence is intentional and is meant to be felt.
Holy water is a sacramental, which means it does not work automatically like a sacrament but disposes the soul and asks for the Church's prayer. The gesture is a renewal of baptism made a few dozen times a year without a word.
Washing before worship is older than Christianity, and the earliest church buildings had fountains in the courtyard where people washed hands and face before entering.
When the fountains shrank to fonts at the door, the meaning shifted from washing to remembering: this is where you came into the Church, through water.
Entirely optional and entirely encouraged. Blessed water may also be kept at home and used the same way.