This is a topic where you can ask specific game-related questions that are not covered by other boards or threads.
Inventory Tips:
The 2nd tab in the Bank (Closet) is cheaper to expand than the main tab, and can still hold everything besides Character-Bound stuff and Weapon Boxes.
Unsealing Charms are used to basically appraise weapons of unknown stats.
Unsealing Charms are incredibly overpriced at merchants. You get them normally from decent odds after clearing a equal level dungeon. The “Survey” system rewards them semi-often at low levels.
If you have obtained some weird item with a colored named that you’re not sure what it does even after reading the description, do not throw away, it will likely be useful later in either Crafting or Upgrades.
If you use a Brilliant Key to open a chest (obtained from the Cash Shop or very rarely in treasure chests), you will always get a weapon for your own class.
Weapon > Soul Shield > Accessory is the order of most to least useful stat giving items. Keep that in mind when looking at prices.
Almost every weapon obtained can be used as feed for leveling any other weapon. Dropped ones, Quested ones, Bought ones, etc. I’m not saying it’s always the best idea (depends on the fee), but it’s something to at least check on.
You must be wearing an Outfit or else Soul Shields will not have any effect.
The Fusion Powder obtained from salvaging Soul Shields can be used to upgrade other Soul Shields.
Breaking a Gem might give you a crystal, however a Gem with a high grade or above will always give you a crystal. Crystals can be used to convert your gems into other types.
Some of the higher priced Soul Shields are bid on in dungeons, including some that are only really useful for upgrading other Soul Shields.

Combat Tips:
Assassins and Kungfu Masters are the more challenging classes for new players.
You will automatically accept special quest upon entering an instance with boss. Do not forget to claim the reward (might contain weapon or accessory) when you have finished the dungeon.
There are 2 modes of grouping: 4 man and 6 man. 6-man rewards accessories and Soul Shields with a low chance of getting weapons, 4-man rewards weapons and outfits along with most of the rare mats (legendaries,etc..) associated with the dungeon, and sometimes weapons.
When your party member attacks with a disabling effect, the enemy will show an aura of a specific color, depending on the type of the effect. If you have a skill with similar disabling effect, use it immediately to disable the enemy through Combination Strike. If you think that your hand might not be fast enough, just press “Space Bar” to automatically use the correct skill.

Repair/Exploration Tips:
You can repair your weapon yourself near any Bonfire or party gathering pillar by using a Repair Tool in your inventory.
Emergency Repair Tools can repair weapons even while in combat.
Always avoid using the Blacksmith NPC repair service. It is VERY overpriced.
If your weapon is fully broken you can immediately equip another one, even if you are in combat mode.
The color of the portal to dungeon shows the difficulty of the dungeon from easiest to hardest: white/gray, green, blue, purple.