Most people agree that there is no one good way to play Pokemon, and that most fun you can have playing these games is building your team and thinking up strategies. However some time ago I've been thinking if maybe there is a way to come up with the most efficient strategy for each of the title in the series.
There are a couple of principles I've come up with, that is:
>score as many one-hit KO's as possible
>take as little damage as possible
>grind as little as possible, but fight all trainers in the game
One could say that the most efficient way to play is to solo with the starter because it's going to be insanely overleveled by E4. That is a viable option and I'm sure many people tried that at least once, but usually there are troublesome roadblocks and you need to help your only Pokemon with some items and rely on luck.
Most efficient run has to rely on fast and strong Pokemon with wide movepools, with attacks that can easily dispose of any enemy at any time. It needs to waste little to no experience points on Pokemon that aren't going to be participating throughout the whole game. It usually prefers smaller teams of four, five Pokemon tops. On the other hand it doesn't allow EV training, egg breeding, and resetting for IVs, because it counts as grinding.
The entire purpose is therefore to find a perfect team that fills the above conditions for each of the games. If you guys have a perfect team in mind for any of the games, I invite you to contribute.