Pokemon go Stardust AND Xp Guide

The item Stardust is an item that can be used to power up your Pokemon, increasing its CP and HP. It cannot be purchased in the shop, and so must be earned by performing certain actions within the game.

 

There are a few methods you can use to earn Stardust:

CATCHING POKEMON

You can not buy stardust, you must collect it by catching pokemon.  Similar to candy, stardust is connected to monsters.  Unlike candy, it doesnt matter where the stardust came from. You can use stardust on any pokemon.  Each time you catch a Pokemon, you'll be awarded 100 Stardust and three Pokemon Candy, specific to the Pokemon you just caught. 

HATCHING AN EGG

Each time you hatch an egg, you're awarded with Stardust, Pokemon Candy, and XP! The amount of Stardust you'll receive depends on how long it took to hatch the egg - 2km, 5km, or 10km.

DEFENDING A GYM

Once the trainer has reached level 5 and chosen a Gym Team, the player can head to either an unclaimed Gym or Gym of the same color, and help defend the gym by placing a Pokemon in the gym.

Once any amount of Pokemon are placed into gyms to defend, check the Shop page and look for a shield icon in the top right. The number inside will list the number of Pokemon you have defending gyms, and once every 21 hours, a Defender Bonus will reward the player with PokeCoinsand Stardust if they tap the icon, increasing the amount for each additional Pokemon currently defending a gym.

You do not need to have a Pokemon in a gym during the cooldown period - to get the reward, you only need to have at least one pokemon in a Gym when the shield icon is not counting down to the next available chance to claim a reward.

If the gyms aren't allowing new pokemon to defend them, the player must train to increase the gym's prestige and increase the Gym Level, to allow more slots for Pokemon.

Stardust is an incredibly important resource. Use it wisely and obtain as much of it as you can!

When to use Stardust

Since stardust is a valuable commodity, it is advisable not to use Stardust unless you can make the most of it. Here are a few tips to keep in mind when using Stardust.

• More Stardust is required the higher level a Pokemon gets - as you increase in trainer level and find tougher pokemon, Stardust will quickly scale to the pokemon's level, eventually costing thousands per power up. With this in mind - try to limit spending too much, when it may be easier to just try and find a higher level pokemon in the wild
• Top off your already powerful pokemon - Since a pokemon's CP can only get so high dependant on your trainer's level, you'll never truly max out a pokemon's CP for good. When finding a pokemon to level up, try to find ones that you've caught or hatched that are already far along the CP bar, where the white line is near the far right in the 90% range. That ensures you'll only need to power them up once or twice per level to keep them at a high level.
• Don't waste Stardust on a pokemon you have no candy for - While it can be enticing to want to power up a rare pokemon you just found, remember that rare pokemon means you won't have many candy to use to power up along with the stardust. Therefore it's better saved for when you catch several of that type, or at least hatch them from an egg - which gives you lots of candy and stardust to work with.

Org story found here 

http://www.ign.com/wikis/pokemon-go/How_to_Get_Stardust