A very basic but fundamentally sound practice to any Christian witch is using the sign of the Cross. The Christian Cross is outward sign of the sacrifice of Jesus Christ. We hold that in our hearts and minds to remember that ultimate sacrifice for our sins.
When working a spell, begin with making the sign of the Cross. This is done by placing index finger, middle finger and thumb together. Then starting at your forehead , touch for forehead saying "in the name of the Father", then touch your breastbone saying "and of the Son", they touching your left shoulder then right shoulder saying "and of the Holy Spirit."
This practice, as simple as it may sound, will protect you by letting all other energies and spirits know you are of God and you are not to be harmed. Another term for this is called "Crossing yourself." You can also add to this practice by dipping your middle finger into Holy water prior to crossing yourself. This will just add to the efficacy of your intention to protect yourself.
Peace be with you all, and enjoy the wonderful practice of Christian Witchcraft.