This is a general guide for the upgrade materials in Destiny. Our source also shared strategies for farming these materials where possible. You can learn more about these locations and strategies here.
Spinmetal
Spinmetal is standard upgrade material for beginner, low level gear. It will also be a required material for some legendaries. You will want to always have a stockpile of spinmetal to keep level 30 gear in maintenance.
Helium Filaments
These are used for some low level gear, but is used primarily to upgrade Legendary armor and weapons. This is the easiest material to farm and is easily found on the moon.
Spiritbloom
Spiritbloom is found on Venus, and is a vital resource for everyone except warlocks.
Relic Iron
Relic iron is one of the most important materials in the game. It is essential to keeping your exotics and legendaries in top condition. It is found in Mars, where heavily armored Cabal forces keep guard over them.
Strange Coins
Everyone needs strange coins, but there are only two reliable ways to earn them every week. The weekly heroic strike rewards 3 coins per week based on the difficulty you finish it on. If you can play this at level 28, you can earn 9 coins. The other way is on the Nightfall mission, but it is extremely difficult to earn here. If you are a high level player, you can earn 18 coins a week using these two methods.
Ascendant Materials
Ascendant materials are extremely rare, and needed for end level upgrades for legendaries and exotics. There are only two ways to farm for it; via the Vault of Glass, or the Daily Heroic Story mission. And the Vault of Glass is the easier option. At Level 28, you can get two materials, and one material at Level 24.
Motes of Light
The motes of light are mostly for buying cosmetics from the speaker. However, if you can collect 23 motes, you can get an exotic engram from Xur. Our source has not really found a reliable, relatively easy method to farm these yet. It is a level up reward for levels 20 and above, it is a strike reward, and it is a crucible reward.
On the side, public events give you an opportunity to earn ascendant materials, strange coins, and mote of light. The first day you complete such an event you are guaranteed a reward package. Rare engrams also give you a chance to decode and acquire these.