Black magick is generally considered any magick that is used on a person without their consent, or to cause harm. Harm can be physical pain, or disruptions in their lives.
We're going to ignore the multiple opinions on colored magick in this thread and use these terms for the sake of keeping it simple.
For every positive in the world, there is and must be a negative to maintain balance. What people do not always consider is that the negative helps pave the way for the positive to shine through.
Each practitioner makes a choice as to what to do with their own workings. Some choose to only do positive things. Others may not. Keeping the idea of Karma and any theories of the Three Fold idea out, negative, black or dark magick exists in the world. That's just a simple fact.
What you choose to do with the information below is up to you. Some may decide to never touch it, but appreciate it's informative value. Others may incorporate it into their workings if they feel the need. That is a personal choice and no one can make it but you.
This is by no means a complete list of anything.
Poppets
Poppets are more commonly known as Voodoo Dolls . They are what is considered to be sympathetic magick or rather "like creates like" (representations). The idea behind a poppet is that you are creating an image of someone and thus, what you do to the doll should happen to the person of whom it represents.
While they can be used for both positive and negative intentions, they are more commonly seen as negative and as such that will be our focus.
Poppets are far more than an ugly little doll you stick pins in. They can be made from fabric, clay, wax or any other material that you can make into a form. Personally, I create them out of felt, large enough to stuff with herbs and written words of intent.
Making the doll can be time consuming. Whether you are cutting and sewing, or molding, each step you take should be with focus of who it is meant to represent. You can go so far as to add personal items of theirs such as hair, nail trimmings, parts of clothing, ect as these items are infused with the persons energy. If you are unable to get these items, you can carve or stuff the doll with the persons name.
Contrary to popular belief, you do not need to know the persons real name to cast against them. If, for example, you were to cast against a person you know only online as a certain name, you can use their username, their avatar, a picture of them, or possibly even a copy of something they wrote. While they may be far away, we leave bits of ourselves with our online persona's. Concentrating on that person as YOU know them, helps create this representation of them.
So what can you do with a poppet? Of course you could stick pins in it. Each pin representing what you want them to experience. But you can also use it to bind, banish, cause harm, influence, ect.
Going back to personal experience, I stuff my dolls with herbs and various other things. If I am feeling particularly nasty, I use "dead" things. Ash, dead bugs, perhaps even uncooked meat. This can represent the death of the person or the death of something you are targeting be it a habit, relationship, magickal working that they have done, ect. You can also write your intent on paper and stuff it in the poppet.
After creating and stuffing the doll, I bind it. Whether it is to bind them to stop them or bind the magick to the doll. Using thread or ribbon, each time I wrap it around the doll, I speak what I am causing to happen.
From there, you have a few options as to what you want to do with the poppet. You can put it in a jar and keep it around so you may continue to add to it from time to time, or you may bury it, sealing the deal. Should you decide to bury it, keep a few things in mind: You do not want to bury it near your house, nor anyone else's house of whom it is not intended for. If you do bury, keep in mind it's location. Should you wish to undo it later, you cannot do so without being able to retrieve it. Some say you can burn the doll, causing the action to speed up. Personally, I do not recommend this as to me it signifies the destruction of the work.
Should you put it in a jar, adding herbs that are binding would be suggested to have at the bottom of the jar or sprinkled over the poppet. Again, this binds the spell and the working.
Herbs
Herbs have been uses in not only magick, but society in general since the dawn of the time.
*Keep in mind that when you look up herbs for your research, you will often find tree's vegetables and fruits. Herbs, in magick, tend to encompass all plant life*
It is difficult to find any reading material (that looks credible) that discusses herbs in black magick, but a little creativity and common sense can go a long way.
If we want to get rid of a person or situation..how would we do that with herbs? We use banishing herbs. They are often consider to banish negativity, however banishing is not limited to negative forces. It is removal. Period.
When casting a spell, what herbs are used is subjective to what it is we are trying to do. If I wanted to remove love between two people, I would use herbs commonly used to attract love and combine them with herbs used to banish. For luck, I would do the same. The list goes on and on from being able to work with some psychic abilities, fertility, protection and even good health.
When looking for herbs used in banishing, keep in mind the word "exorcism". While it is typically used to describe the removing of evil..it is the removing of and thus can be used to remove whatever it is you are trying to take away from that person.
Banishing Herbs (It's a fairly long list)
To use in curses/hexes (what you use for hexing and cursing is also use to reverse it)
Binding (either the person or the spell/working)
*Always remember to research an herb before using it and never digest it without consulting a specialist first. Especially (obviously) the poisonous ones*