Take your broom stick and drill a hole at the top if you choose to. Start wrapping the wire by inserting the end into the hole you just drilled into the broom stick. Wrap the wire tightly and uniformly around the stick until you reach the desired length of your tree trunk. Snip the wire at the wire spool. You can remove the trunk from the stick, one of two ways. Either by removing the end you put into the hole at the top then sliding it off or cutting it at the top then sliding it off.
Now to shape the branches. Take a pencil and the thin wire and use the same strategy, but instead of drilling a hole in the pencil, hold the wire with your hand. Leave a length of wire at the front and the end of the branch.
To form the tree skeleton you must twist the ends of the branches around the loops of the trunk. After you have the number of your desired branches attached to the trunk start forming the other end of the branches. Take the end of that wire and make two hills and a valley shape in the middle and slightly bend these upwards at the top of the shapes. This is so you can hang little spiders or bat decorations off your tree after it is completed.