I nickname them based on weather or not I feel like it and I use names that fit them.
Blaziken is C. Falcon, Terrakion is Roflstompr, Rattata is Top %, My next Heatran will be Rubicante ("The frozen winds of hell's ninth circle could not penetrate this cloak of flame I wear") And my Shiny Haxorus is Fuffy.
I'm not easily impressed; I'm usually oblivious to whatever's in front of me. Stunfisk is the epitome of monstrous majestic legendary creatures that spew fire.
If I feel there is a name I find more fitting for a pokemon than its given name, I'll usually nickname it that; Wotter for Oshawott, Avogodrill for Excadrill, things of that nature. Then I have teams created from characters of my own writing that use the most close relation I have access to as a medium. Then I base all the rest on other characters, lore, regions; I've gone through Africa/Sahara/Mombai/Caineghis, Canada/Arctic/Chicago/Nailah, and Bermuda/Giffca plus two others I can't think of as names for the Legendary Beasts alone, as well as names from Fire Emblem, other games (KingK.Rool for Feraligatr), Lion King (Watchog and Mamoswine)...
"The point of war is not to die for your country. It's to make the enemy die for his."