Here are some other ways to say it:
* Mange tak: This means "Many thanks" and is less formal than "Tusind tak."
* Tak for det: This means "Thank you for that" and is appropriate for specific things.
* Tak skal du have: This literally means "Thank you shall you have," and is a very polite and formal expression.
* Tusinde gange tak: This means "Thousand times thanks" and is even more formal than "Tusind tak."
The best way to choose the right expression depends on the context and your relationship with the person you're talking to.