The following was taken from this page on http://demilunes.blogspot.com. Please be aware that - with the exception of the parts not required for what I wanted to post about - I copied the post directly from that blog, and had nothing to do with the writing of it. I just thought it was useful information and wanted to put it on my blog (if nothing else then so that I can find it more easily in the future). Anyway...
"First, making a potion can be very simple, as it can be very elaborate... I better like simple! Since not all of us has access to bonfire in the middle of a meadow or on a shore, I'll propose you something most of us has but seldom use; a chocolate fondue kit. You know the one you can put a tea light under? It makes reasonable size potion and you can safely brew you potion all day long with that.
Cauldron/Fondu kit/ Pot-pourris Burner
Glass stick, or twig, or wooden spoon (those are great since you can carve symbols into them!)
Mortar and Pestle
Ideally Spring Water, but boiled tap water can do.
Herbs and Essential Oils
Herbs can be substituted by their essential oils, and vice versa. For herbs, you need to crush them hard enough to break them and free their essence, but turning them into dust isn't a necessity.
Previously take your water to boil. By the way, if you don't have any fondue kit, you can make your potion on your conventional oven, you just have to watch it more closely when it brew. Pour it in your cauldron. At his point you can request help from the fire and water element. As a rule of thumb, have about 2 tablespoon of herb for a cup of water. Crush each of them into your mortar and sprinkle on the water. If you feel like strengthening your potion, you can say aloud the name of the herbs/oils you add and why you do so (ex: "Ginger for success", "Rosemary for memory", "Pine for ideas"...).
You can also say something like:
By the Fire and Water,
By the essence of (herb),
Make it as I wish!
When all your herbs and oils are in, let them soak while your think of your goal. Concentrate on it, and when you feel like it's the time, take your stick and stir 3 times; counter-clockwise for banishing potions, clockwise for others. You can also say aloud your goal.
You can also say a more complex incantation, like this one:
By Water and Fire, By the Air and the Earth,
May the hidden powers come to help,
And grant me my wish.
(Ain't it harm none) It is my will, so mote it be!
The potion we made in yesterday was:
Lavender (+ 5 oil drops)
St. John's Worth"