I prefer using a rehairing tool. Those are very simple to make otherwise there are even a few people on here who sell them, one of which is Maniah. I know there are several people who can give you in depth information on how to make one, I am on my phone right now so I am kind of limited to what I can do!
And as far as hair goes, I use Dollyhair nylon. Its very soft and easy to work with. I know there was a thread just posted not that long ago that explained the differences between hair types, maybe someone on here can find that link, I can try to find it later and post it then if you would like