Great questions! I can only answer based on my knowledge.
Whenever you make a wand you want to find it from a nice forest or place where there are a lot of trees. You can make it for whatever purpose you want. I use my wand for everything to be honest. I usually ask a tree(prior to picking a branch), and if I feel it says no then I move on until I feel one says yes. Or you could even use a dead branch that's already fallen due to natural causes (this is what I've done with my current). Remember the important thing is that it's going to be directing your own energy. Now you can empower your wand with certain colors, meanings, symbols, and crystals to represent a certain Magick. I just drew the element symbols on my current, as I use it for any and everything. I also put red, green, blue, and yellow thread around it to also represent the elements. After you find the right stick, (length wise) they say it's supposed to be from the crease of your elbow to the tip of your middle finger. But honestly, as long as it's long enough it doesn't necessarily have to be this. AGAIN, the most important thing is that it's using your energy, so if the energy isn't there to begin with, the wand won't be as powerful. Once you have the length you want to carve it down so that it's more light and the bark is off. You don't even have to do that, but that's my personal choice. You may save the shavings to create your own incense even. Decorate it how you want, make it your own personal art project! After all, it's your wand! Hope this helps!
Blessed Be xoxo )0(