Hahaha no no I get it, I used to be the same way, but I just talked with some friends and did some research and figured out what to do to make a nice competitive team, which is a lot different from an In-game team.
Let's see, some terms here. There are three main classes of Pokemon, Underused (UU), Overused (OU), and Uber. It's based off of the general strength of Pokemon and their base stats (how many stats the Pokemon has to begin with). Stronger and legendary Pokemon go in Uber, and then the next strongest go in OU, and the others go in UU. Some people use a strategy to use UU Pokemon in their team because other trainers don't see them coming.
Anyways, there are different roles that Pokemon take on in a team:
Sweeper: A very, very strong Pokemon whose job it is to beat almost/all the Pokemon on an opposing team, or "sweep" the other team.
Wall: A Pokemon with stronger defensive stats whose job it is to "wall" out the other team and provide lots of defense.
Support: A Pokemon who sets up a strategy for another Pokemon, like setting up Light Screen and Reflect, or Stealth Rock and Spikes, or a status like Toxic, and switches out for a stronger Pokemon who can benefit from the opposite team's crippling.
Wow, that was a lot longer than I expected! Sorry about that. :P Any other questions?