Well, here is how I would create spiky hair. It is unlikely the best and fastest, but anyhow, it is a tip =).

I start of creating the character from a box.



Blocking the shapes out quick



When you have blocked out the shape of the head, you duplicate the head and move the copy over the original, like the image.



Then select the lower partof the head and delete the faces



Select the borderedges and fill the hole with a new face. then push the faces under the hairblock up a bit, so it creates an oval form.



Select a single vertex where you want the large spike-hair to start, then push "Extrude vertex". the vertex will be extruded, and move the new vertex so that it fits with your character. Then push Extrude vertex again, and further shape the hair.



And just continue playing around.



Hope this helps you.