How to get Stardust
Stardust is important if you wanna power up your Pokémon, and really, there are only two ways to get this stuff in the game. Firstly, every Pokémon you catch provides a little bit, so it’s a good idea to catch every single Pokémon you see, regardless of whether you need them or not. Note: Pokémon hatched from eggs provide you with stardust as well.
If that’s not enough, you’ll have to suck it up and take part in dreaded Gym Battles: assigning a Pokémon to hold a Gym for you gives daily rewards in the form of items, like your beloved Stardust for example.
How to get Candy
Example: Wanna evolve that Poliwag into a Poliwhirl? It’ll take a whole bunch of Poliwag candy, which you’ll only get by catching more Poliwags. Each new one you catch nets you a little more, and you can also transfer these excess Poliwags to Professor Willow in exchange for, you guessed it, more Poliwag candy. Collect enough, and Poliwhirl’s as good as yours. Simple as that.
How to Battle
The only place to battle is in a Pokémon Gym, which we’ve already explained are vicious arenas of iniquity and horror, but if you’re dead set on progressing quickly in the game you’ll have to take part.
First and foremost, you’ll need to use the stardust and candies you’ve been collecting to power up your Pokémon so they’ll stand a chance of defeating the gym’s defending team. Additionally, there will likely be multiple rival Pokémon to face off against at those Gyms, so you’ll need to build up a stable of powerful Pokémon instead of relying on one heavy hitter to see you through.
You’ll also want to bear in mind the classic Pokémon strength/weakness matrix. For instance, water types are strong against fire, but weak against grass. Grass types, consequently, are weak against fire, and so on and so forth. Work this into your strategy as you build a well-balanced stable of Pokémon to knock an opposing team from a Gym.