All right, younglings, stop playing dodge-toe with your belt knives and gather 'round. I'm going to tell you a bit about how to make staves. Yes, you too, little Defessus!
The first thing I want to make clear is that a staff is a staff is a staff, whether you're going to use it to knock sense into some lunkhead's skull, or charge it up and shoot shock spells at cliff racers. It don't matter if you're making a quarterstaff or a spell staff, either way it has to be strong enough to withstand the force you're putting through it, and flexible enough not to crack or warp when that force is uneven. This even applies to restoration staves, 'cause healing magic is just as powerful as hurting, and not to be taken lightly.
You're going to want to make your staves out of something like maple, oak, ash, or elm wood, or whatever other dense wood you can find, because it has to stand up to being struck hard hundreds, or even thousands of times. But tough as the grain has to be on the inside, a staff has to be smooth as Dibella's bum on the outside, as the staff wielder may have to grip it on almost any part of its length. You don't want to have to face an angry wizard coming to you with oak splinters in his fireball hand.