If you are reading this far then you have taken the option of dealing with a demon on your own. Going any farther will require great faith and Will on your part to complete even the simplest of rites for exercising a demon. Here is what I know which you will be able to use in your fight.

There are many many varieties of demons, and not all of them are evil but if you are here seeking help when dealing with a demon it is safe to assume you are dealing with the evil variety. It is very important to find out as much information about the demon as you possibly can. Preferably its name, as this will give you direct power over the offending demon though if you see a physical manifestation of the demon at any point make sure to either draw it or write down its description so it can be identified. Once it is identified then you can use a specifically targeted rite to exercise the demon. If you are unable to identify the demon then the task of removing it will be much more difficult but not impossible. For the most part, if a person has become possessed they will not accept help in any form which would involve the demon being removed. Also it is important to know that there are demons in this world which will not respond in any way to any Christian rite of exorcism. Do not despair that it is your faith which is lacking even though the demon will do it's best to make sure this is what you believe. Keep your faith close to you when dealing with this kind of entity as it is one of the best safe guards to not allowing it influence over you. Use holy symbols throughout the house, this will tell you very quickly if the entity is of demonic nature and if it can be turned by your faith. Most demons can be turned by any faith, so keeping this in mind make sure to keep your faith close. I can not stress this enough.

Sweet Spirit Powder
Grind the following together to produce a fine powder: frankincense, honeysuckle blossoms, roses, and vetiver roots. Sprinkle the resulting powder over lit charcoals and burn until you feel the area clear.

Advice from Ludovico Sinistrari, a 17th century monk and demonologist
use any of the following either separately or together in any work to remove a demon:
castor oil
palma christi
coral
jasper
jet

Trapped in a Bottle Banishing
Drop 13 rose-thorns into a jar or bottle, one by one. As you drop each thorn, murmur something like "evil presence, I banish you." Cover the thorns with the petals from one rose, also dropped in one by one as you continue murmuring. Fill the jar 2/3 full with salted water, holy water, rose of jericho water or Notre Dame water. Leave the jar open and unattended overnight. Before sunrise, close the jar tight. Evil should be trapped within. Wrap the jar in dark fabric and bury it far away.

Mandrake Banishing
Allegedly no room is big enough for true mandrake root and evil spirits. Bring mandrake in to force malevolent spirits out. Growing the plant in the residence will also have the same effect.

Exorcism Incense and Banishing Powder
Powder the following: true jet, dragon's blood, white sage, frankincense, myrrh, and vertiver root. Burn them in a censor and waft the resulting smoke around the residence. Use this in conjunction with any other exorcism ritual or rite you wish to perform.