Here is my summary of experience in the past few days
Hope to help new players
simple preparation:
lvl 39 gyarados and lvl 69 gyarados
( h.a and ada or jolly 25+atk 25+spd )
ev atk+spd 252
moves : crunch +earthquake+ ice fang +waterfall ( pp max )
waterfall can Repetitive learning
Operation process:
Trade two mons to a friend, let the friend lend to you, keep two gyarados level unchanged, Repeat this process,Realize convenient upgrades
Suggest elevating trash pokemons to level 20 first
only need one gyarados ,A perfect operation can bring 5 trash pokemon together to level 90 or above
illustrate:
moxie Can quickly defeat NPCs , Mold breaker can defeat sturdy .
If your Pokemon is between level 10 and level 40, lvl 39 gyarados can help them Upgrade all the way to 97
If your Pokemon is between level 40 and level 71, lvl 69 gyarados can help them Upgrade all the way to 97
If your Pokemon is greater than level 71 ,You can directly use level 100 Pokemon
If your friends also have two gyarados ,This may increase your friendship between the two of you^ ^