I did the unthinkable...

I'm playing FireRed and was in the Pokecenter beside the Mt. Moon entrance and was talking that sketchy guy to the left of the counter that wants to sell you a Magikarp for 500, and I. Bought. It.

It may seem like a bad choice, but I'm going to use XP share, walk around in some tall grass, battle all the wild Pokemon and XP share the hell out of Magikarp till it evolves. Thoughts/tips on how to make Magikarp evolve faster?