Specialization Books
Before you buy a specialization book for a vendor, save your game. Then buy the specialization book. You should get a message that says, "Specialization Unlocked." Open the game you saved before purchasing the book. You should have both the book and the gold, effectively getting the book for free.
Level Up
When you reach the Tainted Blood quest in Ostargar, collect the three Vials of Darkspawn Blood but do not collect the Gray Warden Treaties. Then go talk to Duncan. Select the conversation option that begins, "We have the blood, but not the scrolls." The conversation will end, but you will get experience. You can repeat this conversation until you reach the level cap.
Ghost Bridge Solution
In the Secret Ash quest, you will need to get across the Ghost Bridge. Before stepping onto the bridge, go right one, right two, and left three. Then step onto the bridge and then enter right two, left three, and left six. Step onto the second section of the bridge, and then enter right two, right four, left six, right four, left one, and right six. Step onto the third section of the bridge and enter right four, right five, left one, right five, left one, and left five. You will then be able to cross the bridge.
Ceremonialist and Sacrilegious Trophies
Before you ascend to the ashes at the end of the quest, save your game. When you are at the ashes, collect some and add a drop of blood to them. Allow yourself to be killed and then reload the saved game. Repeat this maneuver, this time without adding blood to the ashes. Leave the temple and fight the disciples and you will get the second achievement.