1. Basics
1.1. Infinite XP and Money Glitch

2. Collectibles
2.1. Secret Messages (Archaeologist)
2.2. History of the Chantry Chapters (Chantry Historian)

3. Story-Related
3.1. Stone Cold (Act I)
3.2. King of the Hill (Act II)
3.3. Conqueror (Act III)

4. Miscellaneous
4.1. Exorcist (Found and killed the undying Xebenkeck)
4.2. That Thing Has Legs (Found and killed a Vaterral)
4.3. A Worthy Rival (Earned the Arishock’s respect)
4.4. Demon Slayer (Found and killed the ancient demon, Hybris)
4.5. Dragon Slayer (Found and killed a High Dragon)

Infinite XP and Money Glitch
This Glitch will make the rest of the game pretty simple and you will get all the other trophies or achievements with minimum effort.
To perform this trick you need to find a side quest that has no cutscene in the end! Do what you need to do, go to the location where the quest will end and use your weapon. While putting the weapon back you need to talk to the contact person. Now you just need to press the same button over and over again and your level will rank up faster than you can watch. Side quests can be found throughout the whole game so it is really simple to get this done.

Archaeologist
You will need to find 3 secret messages / enigmas of kirkwall / special codexes each year in kirkwall. There are 3 years, which means there is a total of 9 messages. Actually, there are 4 ‘enigmas of kirkwall’ every year. I show you the 3 easiest ones to get the trophy or achievement fast and easy.
The ones in Act 1 and 2 can be collected at any time. In Act 3 you have to do certain quests (On The Loose, Justice, The Last Straw) to reach the enigmas.
It’s important to know where each Act begins and ends! Everything before the Deep Roads Expedition is Act 1 and everything after killing Arishock is Act 3.
Warning: The 3rd codex is invisible for some reason! Simply go to the shown picture (the codex is inside the right one) and keep pressing the button you’re always using to pick something up (depending on your console).

Chantry Historian
Found all four chapters of “The History of the Chantry,” by Brother Genitivi.
This is pretty simple. All four books are located in the chantry.
Chapter 1: Act 1
Chapter 2: Act 2
Chapter 3: Act 2 (warning: can only be collected during ‘Following the Qun’ Main Plot Quest! Easy to miss. You need to be quick)
Chapter 4: Act 3
Visit the chantry in the beginning of each Act. So you won’t miss them.
Act one ends with the Deep Roads Expedition and Act 2 with the death of Arishock.

Stone Cold
You can not miss this fight, it is a part of the story!
In the ‘Deep Roads Expedition’ Main Plot Quest at the end of Act 1 you will encounter the Rock Wraith. Try to have at least one tank (warrior with good defensive skills) in your team. Use him to distract the enemies from other team members. To have one healer is good on higher difficulties, you can also use Health potions instead.
Hide behind a pillar when the boss is performing special attacks.
It’s recommended to do this on the lowest difficulty. Don’t forget about the fact, that you can change the difficulty every time you die.

King of the Hill
At the end of the ‘Demands of Qun’ Main Plot Quest (Final Quest in Act 2) you will encounter the Arishock. This is a story-related trophy and you have to fight against this beast either way. It doesn’t matter what decisions you make during the conversations.
When the fight starts you should focus on the minions at first. If you skilled the mage ‘Anders’ to be a healer, bring him with you. He can revive fallen comrades. Avelin is supposed to be in your party anyway during this part of the missions so make use of her tank abilities (she distracts enemies, so the rest of your party doesn’t suffer so much damage). Don’t save your potions, make use of them if you need to. You can also change the difficulty every time you die.

Conqueror
This is the final bossfight in Dragon Age 2 – the last task you have to fulfill in order to finish the game. You can’t miss the fight against the meredith. Make sure you are having lots of potions with you, before starting the quest. I suggest a team of 1 tank, 1 healer (Anders, the mage) and 2 damage dealers. The minions will become very annoying as the fight comes to an end. Make sure that your damage dealers are having some good area-wide attacks. Your tank should focus on meredith only. Actually, she isn’t doing a lot of damage. In case you seem to be too weak, let her kill you and lower the difficulty in the ‘game over menu’.

Exorcist
This has to be done in the very beginning of act 2. Right after you come back to Kirkwall from your ‘Deep Roads Expedition’. To find Xebenkeck you need 5 of the so called ‘Evil Tomes’. It’s important that you destroy all of them! After eliminating those books you travel back to Darktown and enter a location called ‘Evil Pit’. You need to have a rogue with you to open a door here! You will reach a room with a huge book inside. Instead of destroying it, you have to read it and accept the conditions. Xebenkeck will spawn now. Kill her at first and focus on her minions later on. You will need 1 tank (warrior with good defensive skills), 1 healer (to recover health of other party members) and 2 damage dealers (mage and rogue is recommended). Take as many healing, stamina and mana potions with you as you can. You are gonna need it.
Don’t forget about the fact, that you can change the difficulty every time you die.

That Thing Has Legs
In Act 2 you will have to fulfill the Main Plot Quest Blackpowder Courtesy. Right after talking to the Viscount Dumar you should travel back to Merrill’s Home. She must be in your party! Have a talk with her and accept her quest. Travel to Sundermount and talk to Keeper Marrethari. Now your destination is the Vaterral Hunting Ground which is a cave at the end of the left path. Go inside and fight your way through the cave spiders until 2 cutscenes start. Now you have to face the so called Vaterral. Don’t forget to take a couple potions with you to stay alive in the final fight.

A Worthy Rival
In order to get Arishock’s respect you have to choose a lot of missable dialogue options. After talking to viscount dumar at the end of the blackpowder courtesy quest, you will be able to get ‘offered and lost’. Before doing this quest, go back to arishock and tell him ‘your delegate is missing’ to earn a huge amount of respect.
During Offered and lost you have to kill varnel. Tell the viscount ‘Do not hide it, he’ll know’.
Another dialogue option that brings a really huge amount of respect is in the beginning of ‘demands of the qun’. You have to find isabela inside the hanged man in order to receive the ‘to catch a thief’ quest. Complete this quest and the dialogue show dialogue options about the relic will be available. Tell arishock that isabela has the relic and the job should be done.

Demon Slayer
This video shows you very detailed what needs to be done to find the ancient demon Hybris and how to win the final fight.
You need to find 3 different scrolls in act 3. Every scroll will give you a side quest. Travel to the hidden lair, marked on your map and kill all enemies. After you finished all 3 quests for all 3 scrolls you can enter the hidden lair in Darktown. Inside this lair is Hybris. It’s good to have a tank, a healer and 2 damage dealers with you. Make use of your potions if you are forced to do so.

Dragon Slayer
This can only be done during Act III. Travel to ‘The Bone Pit’. You should now receive a quest called Mine Massacre. If this quest doesn’t start automatically by travelling there you probably completed the ‘Bone Pit’ and ‘Inside Job’ Quests before. Visit Hubert (he can be found at hightown market) and get the quest there.
Be well prepared before stepping into the fight against the high dragon. This beast is probably the hardest enemy in the entire game. Lower the difficulty to casual and take tons of potions with you. You will need to have at least 1 tank and 1 healer with you in case you want to survive the next 7 minutes.