Do you prefer creating your own storylines and canons between your characters and figure out the schematics later?
Or do you prefer to research strategies and make characters based on them?
Sometimes one, sometimes the other. Sometimes a mix of both as little choices add up and twist the execution during character creation.
My characters and their genesis:
1) Concept first: Wanted to be a older retired militia man who was the ultimate team player. As I always loved playing a Discipline Priest in WoW, the Life Oracle with Life Link, Shield Other and Channels was the perfect fit.
2) Concept first: Wanted someone who was melee-centric and the exact opposite of character #1. I enjoy pro-wrestling, so I decided a big dumb (but handsome and beautiful) wrestler would be fun. Tetori monk.
3) Concept first: Little girl, big stick. Character concept from the old anime trope of massively oversized weapons wielded by petite schoolgirls. Oracle/Paladin (perhaps to be Oracle/Skald depending on ACG).
4) Mechanics first: Wanted to play bad ass Zen Archer. Zen Archer/Inquisitor.
5) Mechanics first: Wanted to theorycraft and play a halfling grappler. Halfling Tetori.
6) Concept first: Wanted to play an old stuffy british colonel who had a companion. Made a Taldan summoner with a walking castle ("fort courageous") as his eidolon.
7) Mechanics first: Wanted to play a guy who only used a shield as his only weapon. Ranger/Horizon Walker
8) Mechanics first: Playtesting a Shaman (who is the daughter of character #1). Shaman of the Heavens.
In the bullpen:
9) Concept first: Al Pacino is the master of all magic...HOOAH! Mystic Theurge who worships Asmodeus.
10) Mechanics first: Superstitious Spell Sundering Pounce barbarian with Spellcraft and Knowledge Arcana as class skills. Barbarian.
Thing to note, all my characters are A) Mechanically sound and B) have solid RP foundations (mannerisms, motivations, etc).