Pokémon GO: 15 Crucial Tips & Tricks The Game Doesn't Tell You
14. Transfer Your Duplicate Pokémon For Candy
Like the main games, across your travels you'll come across a host of similar Pokémon - especially if you're grinding/farming a specific patch of land.
As such, hop in your Pokémon viewer (Pokéball button, then left icon), pick a Pokémon and scroll down.
From here, select 'Transfer' and the Professor will take the creature off your hands, returning 'Candy' relating to the 'family' of Pokémon in return. These candies can be used to force evolutions and increase Combat Power (the universal stat used in battles), so even if you're laden with a ton of duplicate monsters, trade them in and spruce up your main team.