In my opinion, there are three aspects to creating a Pokemon battle in a fan fiction that contribute to the description and results of the attacks:
1.) Genre- if your doing a comedy, then maybe someone getting zapped by an electric attack would stiffen up and fall over comedically, if your doing something more serious then that person might go into shock and have to be taken to the hospital.
2.) Type of Pokemon- if a new born charmander uses ember on you, you might have a slight burn or second degree at most which isn't very serious. If a Ho-oh hits someone with sacred fire... that person should probably be dead.
3.) Physics- pretty much explains himself.
