What pokemon do you use?

Depends entirely on the game because each game has at least one Pokemon that I love to use. In most cases it's Kadabra, but Lilligant and Infernape are also up there. For the most part I can make due with good movepools over good stats, so there aren't many limitations.

I really just use whatever I feel like would be fun at the time? I don't really plan out teams, I just go training and catch whichever 'mon seems like a good idea. I do keep my starter every time and I always have a flier and a surfer, but they're never set in stone from the get-go. I also try to have a fairly balanced team but I make it up as I go along so that doesn't always work haha.

I used to play a long time ago, i used teams with good strategies from what I remember.

I use Pokémon that are good competitively and look cool at the same time.

I use Movesets and Attack and Speed Stats.
Take Infernape, for example.
Defense Sucks. If Dragonite used Surf, your a goner, and thats without stab.
Yet if Infernape uses U-turn, it's practically Guaranteed to go first, and you do fair damage, and you can switch to a Pokémon like Mamoswine, which is a all rounder, to finish it off. :)

I use whatever Pokemon are capable of hitting fast and hard. So that means no slow Pokemon, such as Throh or Slowbro.

Designs don't bother me much, I'll use it if it's strong, not good looking. With the exception of Wigglytuff