Abing, how do you evolve your Pokemon in Pokemon Go? Also, Great Balls are proving to be not so great. They don't seem to snap up high-level Pokemon or even very low-level Pokemon. Talk about frustrating.
Magikarp needs 400. xD xD Gyarados is freaking special.
It might help, when you're catching pokemon (with either great ball or just pokeball) to spin/shake your pokeball before throwing it (you get curveball exp bonus +10). Also, use try to get great throw as much as possible (+50xp) and high chances of catching high-level pokemon.