>>32720225There's no wrong way to play, since everything you put coins/diamonds into will help in some way. You are, however, going about things inefficiently.
So, you put all your money into training gear so that you only have three berries? Get as many coin multipliers together as you can, buy whatevers available, and focus on maxing out the smaller stuff first.
Get enough candies to max out piplup so you can make the most of training. Stay on 1.02 so you can exploit the Expert League 3 to get diamonds.
That's about the only advice you can get, there's not much to the game and most shit is totally random.