Lets start out with some recommendations to get most of your farming.
-Be Lv70. Highly recommended to unlock most of these.
-Get VIP, with this you get bonus rough AD and other benefits.
-Have fast mount, this is highly recommended to save time a lot.
-Save up some things for Events such as 2x Profession Recources and 2x Enchantments and Runestones.
-Remember to invoke to get Rough AD bonus.
-Guild Boons
Utility: Treasure Hunter Boon, at rank6 & up you will get 2x profession recources.
Utility: Mount Speed Bonus

AH=Auction House
AD=Rough AD

Daily Dungeons, Skirmish and PvP
Do your dungeons and Skirmish daily with all your characters. Its easy AD. Don't be lazy.
And PvP but i'm sure most people will not do it.
I recommend running Cloac Tower 2 times with each character. Since its easy and fast.

Weekly Quests from campaigns. 4500 AD Each.
-Protectors Enclave: Portal to Tuern
-Well of Dragons: Reclaiming the Hoard
-Sharandar: The Arcane Reservoir [Thaumaturgic Stones are Bound to you]
-Mantol-Derith: Ballad of Baphoment [Need to have completed Maze Engine Campaign]
You also get Resonance Stone, sell at Auction House.
-Caer-Konig: Biggrin's Tomb

Daily Quests and Items to sell.
Mantol-Derith:
400 Rough AD and Lesser Resonance Stone, Sell at AH.
Drowcraft Pants and Shirt. You can buy these from the campaign store or talking to Armor Dealer.
Unlike other Drowcraft gear, these are not bound by pickup. So you can sell them at AH.
Sharandar:
-9 Lesser Thaumaturgic Stones and 3 random from lair/dungeon Style quest. Sell all at AH.
-Potion of Heroism, costs 15 Cold Crescents. Sell at AH. Buy from Thradisar Starwise.

Professions
-Craft items and Sell.
-Some recommendations are Alchemy and Leadership.
With leadership at Rank 21 you can get Refinment items that you can sell at AH.
With Alchemy you can make some Professions Recources like Unified Elements.

Salvage Items.
What can you salvage? Items you get from Epic Dungeons or underdark skirmish.
You can salvage items like Alliance Armor, Underdark Rings and anything similar.
How do you salvage? There is areas where you can salvage, near salvage anvil.
There is place at Protectors Enclave, near Hieronymous Glim. At Seven Suns Market.
Right click item and it will have Salvage Option.
How you get them?
-Spend seals of elements and Seal of Protector to buy Alliance or Elven gear.
-You can spend Guild Marks for Guild gear and salvage them.
-Underdark rings, highly recommend farming Throne of Dwarven Kings for these.
-Glory, spend Glory on gear that you can salvage.

[Guild Marks]
-Spend your guild marks on Explorer's Cases. 3000 Guild marks for 1 Case.
What are they? When you open them you get a quest to locate untapped resources. Map will show where they are.
Sell whatever you get. Check AH about the Masterwork Professions items you can get.
Buy the Case with the most profit.
Locations for untapped recources
-Vellosk
-Whispering Caverns
-Mount Hotenow
-Pirates' Skyhold
There is also Traveling Merchant which sells some Masterwork Professions Items.
Those will not be bound to you so sell at AH.

VIP
-Get VIP. This is the best thing in the game because of so many benefits the higher rank you have. Lets see
Free Enchanted Key, just straight up profit. Open Lockbox and sell whatever you get or dont need. Easy AD.
Free Epic Dungeon Chest Key, can get up to 3 of these a day on all characters.
15% Bonus Rough AD for some places.
Summon Traveling Signpost, easy to travel. Don't need to run around the places anymore.
Invocation anywhere.
Immune to Injuries.
Summon salvage anvil.
10% Salvage Bonus
No Auction Fees, the big thing you will need. Will save so much AD.
10% Bonus to XP, Glory and Profession XP.
For full benefits list:http://neverwinter.gamepedia.com/VIP_Program

Experience Rewards.
You can get 30,000 Rough AD from these, and some Refinment items like Black Opals.
AD reward is not that rare, i get this maybe every 1/3 rewards.

Glorious Resurgence Lockbox.
Save these, once other lockbox comes in other people want these. They can sell anywhere from 1,000 to 3,000 AD for 1 lockbox.

Events. Winter Festival, Halloween and so on.
Take advantage of these, most of these have Professions for limited time.
So sell professions stuff other people need, prices will be high.
And sell whatever rewards the event is giving at AH.

Auction House.
Buy when prices are low and sell back when prices are high.
This can require huges amounts AD to make big profit. But it will be huge source of AD later.
Example: Buy refinment items long before 2x Refinment points is coming. Once its released, prices will be high.

Campaign Task
-Make Enchantments and sell them at AH
For Example: Dragon's Hoard Enchantment, Fey Blessing Enchantment.

Ardent and Celestial Coins.
-Buy potions and sell at AH. This is optional.
For Celestial Coins you have chance to get Coalescent Ward (Bound) so you might want to save them.
With Ardent coins, there isn't really anything that's valuable other than potions so buy them.

Best Dungeon/Skirmish to farm?
Dungeon: Shore's of Tuern and Castle Never
Why Shore's of Tuern? Not that hard, easy to find queue.
Why Castle Never? Its got tons of rewards. You can even get Rank 8 Enchantments.
And chance to get Shard of Orcus which is worth 5-6Mil AD. And Underdark Rings.
Skirmish
Throne of Dwarven Gods.
-Hand's down the best skirmish to farm, easy and fast. Plenty of players doing it.

Well this was my guide for how to farm/get Astral Diamonds. You can easily get 200k AD in a day with just 1-2 characters alone. So if you have more, the more profit. :)
Hopefully this was helpful to you, if you have any kind of feedback for the video or this guide feel free to tell me. Be it good or bad.