The wand is usually cut to the length from the crock of the elbow to the tip of the forefinger but as long as it is fairly straight and comfortable to hold the length doesn't really matter. Willow, elder oak, hazel and fruit trees are some of the traditional woods for use as wands. It's best to take the wood from the tree when it is dormant over the winter so the holidays of Samhain and Yule are best chosen for this purpose. Wands can also be made from crystal and metal but wood is more traditional.
Once the wand is cut it can be carved and painted and have gems or other things attached to the end to give it a more personal appearence. It should also be remembered that the more time and effort you spend making a magickal item the more powerful it will be when created.
The wand is a tool of the south and therefore associated with fire but the wand also stands for communication and matters of buisness.