I've now realised it's pointless powering up your Pokémonz, spent loads of stardust on my Golduck only to evolve a Psyduck and get an even more powerful Golduck..
Transfer away all of the ones you've got, or would just evolve into something you've got. When you've maxed out your candies on those, stop collecting them and get your stardust elsewhere.
This. Not sure what to do.