Sign of the cross

More Christians than not use the sign of the cross as a reminder of who and whose they are. It's a custom/sign that goes back to the very earliest Christian communities. And in those days, it could have been dangerous.

“When, then, you make the sign of the cross on the forehead, arm yourself with a saintly boldness, and reinstall your soul in its old liberty; for you are not ignorant that the cross is a prize beyond all price.

Consider what is the price given for your ransom, and you will never more be slave to any man on earth. This reward and ransom is the cross. You should not then, carelessly make the sign on the forehead, but you should impress it on your heart with the love of a fervent faith. Nothing impure will dare to molest you on seeing the weapon, which overcometh all things.”

– St. John Chrysostom

"The sign of the cross is made by placing the thumb and the first two fingers of the right hand together as a reminder of the Trinity. Touch your head at the naming of the Father, then bring your hand to the middle of your chest (over your heart) at the naming of the Son. At the naming of the Holy Spirit touch your right shoulder and then your left shoulder.

But let us be clear, making the sign of the cross, or not making the sign of the cross, is part of our Christian liberty. It should never be made a criterion for being viewed as more or less confessional, more or less liturgical, or more or less Lutheran. While the sign of the holy cross is the property of each and every baptized child of God, it is up to the individual to determine when and how he or she will use it"