Unless we avail ourselves of the protective capacities of God, we leave ourselves vulnerable to the attacks of the evil one. These prayers are offered as a way to preempt those attacks and keep oneself and one's loved ones under the protection of God.
"I sign myself with the sign of the cross (do it) I cover myself with the Blood of the Lamb (some motion to convey covering) I surround myself with the Light of the Cross (describe circle around you) and in the Name of Jesus Christ, nothing shall come through to hurt me."
Then put the Blood of the Lamb and the Light of the Cross on your loved ones (one-by-one), home, vehicles, place of work. Then on any special cases or needs--the sick, those traveling. Then on any you think the Lord has given your responsibility for--governmental officials, missionaries, schools, airplanes, athletes, soldiers, etc. Finally: "I assert now that I and those I've prayed for are fully protected in body, soul, and spirit, in mind, will, and emotion, in circumstance, relationships, and finance, and against all the assaults of the world, the flesh, and the devil."
Another form (from my book, Holy Vulnerability) based on Eph. 6:
"Lord Jesus Christ, I greet you this morning as my commander and chief, reporting for duty. But first, I need to clothe myself with your armament, for my own is of no use against the enemy. Therefore, I take to myself the belt of truth. I will desire, speak and act in accordance with the truth. Second, I take on the breastplate of righteousness. Thank you that this is your righteousness, and that it protects my vital organs, especially my heart. I will speak, think, and act righteously. Third, I put on the shoes of the gospel of peace, and I will prepare that good news by reading your word and by being ready to give an account for the hope that is in me. Fourth, I take on the helmet of salvation. Save me, Lord, from the world, the flesh, and the devil. And I will trust you to give me the mind of Christ and to think your thoughts in my mind. Next, I take the shield of faith by which to quench all the flaming arrows of the enemy--arrows of temptation, accusation, deception, and harassment. Finally, having seen to my defense, I take the sword, that particular word which the Spirit gives, to utter against Satan in whichever way You lead. Over it all, Lord, I take the mantle of love, asking you to give me your love for all whom I encounter today. I decide by this that I am effectively armored for whatever spiritual warfare comes my way today."
Then ask for protection for others, as indicated above. Finally: "I assert now that I and those I've prayed for are fully protected in body, soul, and spirit, in mind, will, and emotion, in circumstance, relationships, and finance, and against all the assaults of the world, the flesh, and the devil."
(When it seems as though you might be under attack, use this prayer in addition to one of the above:)
In the name of Jesus Christ crucified, died and risen, I bind all spirits of the air, the atmosphere, the water, the fire, the wind, the ground, the underground, and the nether world. I also bind the influence of any lost or fallen soul who may be present, and all emissaries of the satanic headquarters or any coven of witches or warlocks or satan worshippers who may be present in some preternatural way. I claim the blood of Jesus on the air and atmosphere, the water, the fire, the wind, the ground and their fruits all around us, the underground and the nether world. Lord, I ask You to bless our enemies by sending your Holy Spirit to lead them to repentance.
In the name of Jesus Christ I forbid every adversary mentioned to communicate with or help one another in any way or to communicate with me, except as I permit.
In the name of Jesus Christ I seal this place and all present and all family and associates of those present and their places and possessions and sources of supply in the blood of Jesus. (Repeat 3 times if you think someone has cursed you.)
In the name of Jesus Christ I forbid any lost spirits, covens, satanic groups or emissaries or any of their associates, subjects or superiors to harm or take revenge on me, my family, my associates, or cause harm or damage to anything we have.
In the Name of Jesus Christ and by the merits of His precious blood, I break, decommission and dissolve every curse, hex, seal, spell, sorcery, bond, snare, trap, device, lie, stumbling block, obstacle, deception, diversion or distraction, spiritual chain or spiritual influence, every temptation, accusation or harassment, also every disease of body, soul, mind or spirit placed upon us, or on this place, or on any of the persons, places, and things mentioned, by any agent, or brought on us by our own mistakes or sins. (Repeat 3 times if under a curse). Amen.