Ive done the three quests involving the skooma trade, but when I talk to the Jarl or her steward they dont offer me the house, what else do I have to do?

You have to do at least five favours for the citizens of Riften before you are offered the house for sale. The last two quests for the Jarl count so you need three more. Some take longer than others to complete. Speak to the Jarl's son who asks you to collect his weapon from the blacksmith which is probably the easiest one. I think even giving a coin to the beggar in the market counts as well but I'm not 100% sure. The house in Riften is by far my favourite in the game.

Iron.

You can pick up her father's dagger from Alessandra (in the Halls of the Dead under Temple of Mara) to take to Andurs in Whiterun, really easy. And I always do Wylandriah's running around, and help Brand-Shei find out more about his past.

Even fetching beers for drunken tavern people count