ok, my friend is going to do mine this weekend and need to know how to space the hair when doing them... and what brush to use?
however you want, really. some people section off squares with rubber bands (make sure to get those bands out, though, cause they'll melt and goo into your hair before long), some people just grab sections and go with it. it depends on if you want really uniform or sort of random sized dreads. and use a metal flea comb, you can find them at pet stores.
some people use rubber bands for the sectioning. i don't really recommend it, but it's up to you. i just had my friend grab random chunks of my hair so i can't really speak to how sectioning works practically.
Ive heard that sectioning them with a hexagon shape at the base is quite good because it avoids tugging in a particular direction. Also, if your friends too poor to buy acid (or doesnt want to buy acid), he/she can just stare at the tesalations on your head!