Here is a prayer/invocation of Thor that I have written for protection from harm, enemies, curses, and evil spirits.
I recommend lighting at least one Candle before you for Thor. 4 or 5 Candles seem appropriate to me, since 4 is a number of Jupiter and 5 a number of Mars. A temporary altar can be set up for this, which can be a bookshelf or table or another appropriate surface. But an altar isn’t necessary, in which case it can be good to stand outside, and pour out a drink.
If you would like to give further gifts, burning Frankincense is good! And an alcoholic drink to be given as a libation. Any alcohol is fine, but perhaps sweet ciders, mead, or whiskey is especially appropriate. Alcohol brewed from plants that have especial strength or that grant power in battle or raises one to virtue and banishes evil spirits are also appropriate!
Appropriate fruits can also be set outside as a gift. Or placed onto the altar for some time, and then set outside.
Set up the Altar with a White tablecloth, if possible, or one of another appropriate colour. Then light the candles, and burn the incense, and begin the invocation.
"Hail Thor! Son of Óðinn (Othin/Odin) and Jörð (Jorth)
Oh Holy God, who wields the mighty hammer Mjölnir, you who are the protector of Mankind, the destroyer of evil, who dwells in the great hall of Bilskirnir, in the holy land of Þrúðheimr (Thrúdheim)!
Thor, you have great honor, you are upright, and your might and strength is unmatched! You are friendly and come swiftly to the help of those in need. You are the life-giving lightning, and your voice is the thunder! You unite Heaven and Earth.
Oh, holy, holy God, you are far above this world, you are a shaper of Stars, you govern this world with your benevolence, bringing vigor and strength to it! There is nothing in this world that can stand against you, nothing can best you, you overturn swords and axes and this is of no effort to you, there is no spirit you cannot drive away, there is no curse you cannot break!
Oh, Thor, I ask that you be with me here and hear my petition. Cleanse me from evil spirits and spiritual leeches. Like how the holy rivers wash us clean from all filth.
Thor, I ask that you protect me from harm, protect me from my enemies, that they may do no harm to me, and protect me from curses, let them swiftly be broken, and protect me from evil spirits, let them flee from me!"
You can visualize the goals having been accomplished as you say them, or after they have all been said.
Conclude the ritual by saying “It is done”, and thank Thor for his help and his blessings.
Then you may give the gifts:
“Thor, I burn these candles, this incense, and pour out this drink, as a gift to you!”
Then you may go and pour out the libation in an appropriate place. That can be on plants (If the plants won’t be harmed by the drink) or on the ground outside. Then, if you’d like, you can say a final “Thank you, Thor”, or “Hail Thor!” to conclude the ritual.