Gen 1: Charmander
Gen 2: Totodile
Gen 3: Torchic
Gen 4: Piplup
Gen 5: Snivy
Gen 6: Froakie
I generally like to keep my teams as balanced, type wise, as possible. Trying to cover weaknesses of my own and opponents' pokemon.
I generally like to get as competitive with my movesets as possible without requiring any breeding.
I am completely perfect with how I want my levels. Everything must be even except for major boss fights (gyms, team admins, etc.). If I know that a certain pokemon will sweep through their team, I leave them a level or two behind so afterwards, they end up even.
I generally lean towards having a pokemon of the starter typing trio (Water, Fire, Grass), and having at least one steel, dragon, or fighting type to try to cover everything. Steel, is always a necessity for me, and I often find myself having more than one steel type on my team. Mainly due to my expertise in that monotype when it comes to competitive battling, I find steel types to be a nice touch.
I always try to vary what pokemon I use. So let's say I use lucario in 4th gen, I try my hardest to stay away from using it in 5th/6th gen.
I tend to over buy items once I get to the top tier (Hyper Potions, Ultra Balls, Etc.)
I generally don't catch many pokemon aside from the ones I end up using on my team.
I usually get a pokemon with the same typing as the signature legendary so its an easy transition to the legendary which leads me to my next fact.
I want to destroy my opponents, sweep them. That's why I generally use the legendaries, for extra sweeping power.