Talk to any blacksmith or merchant, go into the (Trade/Repair) dialogue, then right-click on things in your inventory to sell them, things in his inventory to buy them.
The color indicate the type of dangers waiting on the other side and whether you can use it or not.
Some special crafting materials can only be obtained by extracting them from magical items. There is an Extractor in the field outside every town. You can extract items one at a time or up to four at once. Odds of getting materials improve with the number of items inserted and their Rarity and Rank. Be aware, though, that Extraction can fail and you can receive nothing. At least if you sell the item you know you will get coin for it.
Crafting is accomplished through Blacksmiths or Crest Scholars.
If you die in a dungeon you have two choices: "Revive" or "Return to Town". If you Return to Town your equipment suffers more damage to it's Durability which can be repaired at any blacksmith or merchant.
Revive requires that you have a Life Stone or a Resurrection Scroll. You get 5 Life Stones per day. Resurrection Scrolls are gained as you level or can be purchased in the Dragon Vault. Press "R" to revive (you will be immune to damage for 4 seconds). Resurrection Scrolls can also be used to Revive a party member if he is out of Life Stones and has no scrolls of his own.
Dragon Nest has no mounts at this time, but there are three ways to move around more easily.
The Nexon cash shop currency, , costs $5 USD for 5,000, so each 1 is worth $.001 USD.
Move around the mobs in circles until you see them clump up, then let loose with a special attack or Area Effect attack. Moving when not attacking will also help keep them from hitting you so much.
"I have looked all over dungeon Y and cannot find this X I am supposed to find. WTH is it?"
Most items you need to interact with will glow when you are near them. Also, many will display a yellow text message across your screen to tell you the item is near. Items can be hidden inside other items, such as barrels, boxes, tents and even chests. If you are looking for something, destroy everything!
Enhancing to +6 can fail but has no chance to destroy the item so you have nothing to lose. ALWAYS enhance to +6 if you plan to wear it. Above +6 you need Item Protection Jellies (from the Dragon Vault) to protect the item from destruction if you fail.
You will automatically regenerate to full HP and Mana the moment you leave the dungeon, but inside you may need a little help. There are potions that can be bought with in-game coin, and Cash Shop potions that can be bought with NX, but the number one way to restore HP and Mana inside a dungeon is with dropped food, drink and herbs. But be careful! Some consumables in dungeons will be tainted and will actually hurt you! Be sure to read the name above the item before you pick it up! Edibles do not go into your inventory, they are consumed immediately.
See Food for a table of all the dropped food and drink, and what they do to you.
At the end of a dungeon you are offered the choice to exit to the "Nearest Field", or "Town". Town will take you to the last town you were in.