"Voodoo Doll" has come to be the standard term for any kind of magical poppet or doll-baby, and especially those which are intended to bring influence on a specified person. Virtually any kind of material can be used to make these dolls, just as long as the final shape is recognizably humanoid. Some people even like to save themselves time and use store-bought dolls or figurines around which to build their dolls. Denise Alvarado's book Voodoo Dolls in Magick and Ritual has many interesting photos from her collection showing how they can be made.
The first step in making a voodoo doll really depends on how you intend to use it. By knowing this, you'll be able to decide what size and shape of doll will best suit you. For example, do you want a doll that's small enough to conceal around your home or someone else's? Do you want a doll that is flexible with bendable arms and legs, or would you be fine with an immovable doll made from wood or clay? Do you want a doll that can be "hidden in plain sight" by passing for a decoration? These must be considered before beginning. Some spells are even specially designed to use a particular style of doll and won't work with another: a spell where you crush and shatter the doll, for example, demands a brittle substance like clay, porcelain or plastic be used to make the doll. One where you burn the doll requires it be made from something flammable in which case clay or porcelain wouldn't work at all, but cloth or herb-bundles can be used. A spell where your doll is stuck through with pins demands using a doll making material with enough give for it to be pierced through.
First determine what you will be wanting to do with your doll and then, with that known, you will be able to determine what substance is best to make use of.
Once you have chosen your type of voodoo doll, as described in the previous post, you will need to "fix" it so that it will be a magical doll instead of a regular toy or trinket like any other. First you will want to acquire any herbs, curios or powders you mean to use, as well as any personal concerns from the person the doll is to be used on (if indeed you mean to use it on a specific person.)
If your doll is made from cloth, you will typically cut it open and place the herbs and concerns inside of it, then sew it back up. If your doll is made of a hard material, you can either carve out a space to hide the additional ingredients and then seal it up again with clay or wax, OR, you can do a traditional African trick of rolling up the herbs and things into a little cloth collar for the doll (or more modern, make a little hanging neck sachet for the doll.)
Some herbs and spices you may want to consider using are:
Red pepper (used for hexing and revenge, also for protection)
Sandalwood (protection, purification, peace)
Cinnamon (love and money)
Patchouli (control and influence, also for love and money)
Sugar (used for any situation where you want to "sweeten" a person's behavior or experiences)
Spanish moss (traditional stuffing for Southern style voodoo dolls, usually for harmful magic)
Master of the woods (for controlling and for mastery)
You can also use other power items to increase the power of your doll, like small talismans, or special items like coins or charms. I know one woman who used a piece of stone from the top of a pyramid in order to create an incredibly powerful voodoo doll: she sewed it up inside with the rest of the materials.
When it comes to creating a voodoo doll, the final step in its making is its being conjured. By this point the doll should be built and filled with any herbal supplies one might wish to use.
Denise Alvarado recommends that the practitioner start this process by anointing his own self with Holy Oil or Seven African Powers Oil, and praying or meditating upon strength and aid in accomplishing one's goals till achieving a trance-like state.
Now, the doll itself needs to be activated by being baptized as the person of whom it is meant to effect or represent. cat yronwode describes on her Practical Tips page having seen this done:
He held the doll-baby in his left hand on its back, drewa cross over it in the air with his right index and middlefinger (like a Christian blessing gesture), and then heldhis open, slightly cupped right hand, palm down, in the airover it, but not touching it, as he said:[John Doe] you are,[downward stroke of cross on name]And [John Doe] to me[cross-stroke of [c]ross on name]You will always be.[hand pauses, then over dollie for next part]You will think what i tell you to think,Walk where i tell you to walk,Talk when i tell you to talk,Do what i tell you to,Go where i send you,And speak when you're spoken to.In Jesus' name, Amen."
I personally like using an oil with which to baptize the doll -- often an appropriate Zodiac oil to the spell target, as I described in my book. Any suitable condition oil may also be used. Holy water or other sacred waters too are acceptable.
Once the doll has been activated, it is ready to be treated in whatever manner you have in mind -- hurt it, love it, manipulate it, whatever.