Taken from the Bethesda Forums
"Where do I start Hearthfire?
If you have already completed tasks for the jarls of Falkreath, Hjaalmarch, or Dawnstar and earned their trust, you will receive a letter from the steward of their respective towns letting you know that land has become available for purchase. Receipt of this letter is required in order to be able to purchase land. You will receive a iscellaneous objective, and a quest target that points to the Steward or relevant authority of that hold.
If you have not yet earned the trust of the Jarls, you will receive a letter via Courier once your character is level 9 or higher. The invite will allow your character to visit and learn about the benefits of working for them and the possibility of buying land. If your character is already level 9 or above when Hearthfire is first installed, you will soon receive the letter from a Courier while visiting a town or settlement.
How do I gain the ability to purchase a land plot?
You must earn the trust of the Jarl for the area you wish to purchase land in (Falkreath, Hjaalmarch, or Dawnstar). Each hold requires some specific favors or quests to be completed to earn that Jarl’s trust. After doing these, you will receive a letter informing your character that the land is available for purchase. This letter is required for purchase.
What are the specific requirements for getting land in each hold?
For Falkreath: You must complete the “Rare Gifts” favor, and the “Kill the Bandit Leader” favor. You may then buy land from Steward Nenya.
For Hjaalmarch: You must complete the quest “Laid to Rest”. You may then buy land from Steward Aslfur.
For Dawnstar: You must complete the Daedric Quest “Waking Nightmare” and then the favor “Kill the Giant”. Please note that this favor has the prerequisites of being level 22 or higher, and having had previously completed the “Waking Nightmare” Daedric Quest. At this point, you can then buy land directly from Jarl Skald the Elder."
I was stuck with Falkreath but i did all the misc rare gift quests, once i did all them i was able to buy land from the Jarl in Falkreath.
"Rare Gift Quests
Getting the book The Mirror for captain Aldis in Solitude
Getting a Mammoth Tusk for Ysolda in Whiterun
Getting the book Song of the Alchemists for Lami in Morthal
Getting the book Night falls on Sentinel for Rustleif in Dawnstar
Getting an Amulet of Arkay for Torbjorn Shatter-Shield in Windhelm
Last edited by iNu; 09-06-2012 at 11:54 AM.