Yes i know this is the first post in almost a year but.......
Well i hope this helps. To extract the thc from marijuana the most effective method is liquid-liquid extraction using butane, or chloroform and lab equipment.
Robert A. Nelson: Hemp Husbandry ~ Cannabinoid Chemistry (Ch 6)
There are better websites that are easier to understand just google it. The alternate method that is the easiest to perform is using as close to pure ethanol as possible (190 proof everclear). Soak the plant material in the ethanol for at least a few hours. You can heat it on an electric stove if you want (it will help the solubility of the thc into the ethanol). CAUTION NEVER DO THIS WITH AN OPEN FLAME. The ethanol will explode and you will burn. After a few hours strain out the plant material. If you want you can repeat the soaking process with some more ethanol to ensure you got every last drop of thc. Then you can either leave out the mixture (that should be a very dark green) until most of the ethanol evaporates, or heat it gently (NOT WITH AN OPEN FLAME) to futher condense it. Dont let it get too thick, if it does just add some more ethanol.
Every time i've made it, i just soak, strain and let it sit to allow a good amount of the ethanol to evaporate. I personally never heat it. I guess im just too scared of screwing up and starting a fire. I use an ounce of schwag that i put through a grinder (after removing seeds) that i put in a mason jar. I cover the powdered pot with everclear close the lid and shake it every few hourse for a few days. (make sure to keep the mixture out of the light as UV rays will greatly affect the potency) Then i just strain through a silkscreen into another jar that i leave open for another day. Then i transfer the mixture to brown glass bottles with eyedropper caps for storage.
If you get the general principal you can adjust the process however you like. Just remember use a liquor with the highest proof you can get (190 everclear) if you use anything with a lower ethanol content it wont work as well. (it will still work though)
One other thing, you might want to read a book call "Stir Crazy, cooking with cannabis" published by "Quick American"
ISBN 10# 0-932551-30-0
ISBN 13# 978-0-932551-30-6
They cover ethanol extraction in the book as well as cooking and other extraction methods, such as using milk, or butter. (thc is very soluble in the fat found in milk and butter)
i hope this helps, keep in mind there are many, many books, articles, websites etc. on this subject , so just keep looking. (second, third and fourth opinions are always worth listening too)