First are foremost, do not in any case draw blood if you do not find yourself in a healthy position to do so. Do not draw blood from any source if you do not possess the knowledge on how to do so. Remember to have any items you use physically clean and sterilized. Lastly, if you start having any symptoms, cease the ritual immediately.
This article was made by me, making it a UPG - Unverified Personal Gnosis.
What you need:
A needle or lancet
A paper sheet
Your first step should be to ignite the candle. Now it's time to draw blood. Take the lancet/needle and use it to pierce your finger, you should have access to your own blood now. If you can not accomplish such, do not keep trying, cease the ritual and you may try it at a different time.
After the initial steps you should call upon what deity you follow, if you do not follow a deity, simply use the flame's spirit as the substitute. After this, state what it is that you desire, be specific. Example:
"Oh spirit of the flame that is here before me, I ask thee to bring me good fortune for as of late my luck has been on the down in the slums and unfortunate events have been occurring left and right. I ask thee to hear thine prayer and relieve me of this negativity bestowed upon me. Oh spirit of fire, purge this negativity from me, renew me as a phoenix from its ashes."
Take your finger and let a few drops of blood fall on to the candle, keeping in mind to not be too close since blood may have a popping reaction, like grease mixed with water. This serves a purpose of an offering for the deity you have called upon.
Your next step is to write in your own blood what negativity you desire to banish. It can be in the form of Sigils, any language, whatever your heart claims. Of course, if such does not work you may use a red pen to represent your blood or a special mix of your own that also represents it.
Your last step is to burn the paper after you write it, while visualizing the flame purging the negativity from your life. After it's completely burn, see yourself revitalized and revived like a phoenix from its ashes.
I hope this works for you and please be careful!