Hey, I just posted a section from my NaNoWriMo novel on ff.net about the main char having a tonic-clonic. The whole novel is pretty explanatory about seizures, as she begins having simple partial seizures due to a head injury and they get progressively worse until she has a tonic clonic and then later goes into Status Epilepticus. :) But Chapter 13 is pretty much all you need for TC's.

http://www.fanfiction.net/s/5651461/13/

Hope it helps!