Bottle trees are traditionally placed on dead trees. We have an old fruit tree by our house that has been a bottle tree for years. You can get a six or eight foot post put it in the ground and use it if you don't have a dead tree.
Use 8d, eight penny, nails at least 3 1/2" long to hang your bottles on. Nail them at an angle down or straight up and down so the bottles stay on in a wind storm.
Bottles: I like to use old soda bottles: Coke, Orange Crush, Dr. Pepper (this is Texas) you can use beer bottles, milk of magnesia (blue bottles were prefered in the old days and many a bottle tree was all blue glass bottles) Any pretty glass bottles will do.
Hanging the bottles: Mix up the colors, find a good mix, add a nail where you feel like you want a bottle to go. You can put all the same type of bottles if you only have one kind. Your choice is up to you.
Bottle trees add a traditional flavor of the South and country living to your farm, ranch or suburban country home. And they will protect your family from evil spirits.