I agree with the person above, but also, when I did my Sora wig, I actually stuck skewers in the base of the wig head and duct taped it to the wall, Gravity helps a lot when making huge spikes!
Aquanet is god, and...dont rush it. if the base of the wig isnt teased already, tease it where you want bigger spikes, and then put other hair around it so it looks smooth.
hair glue the tips of the spikes,if the hair at the top will stay together, the rest of the spike has a better chance of staying together.