When one of you receives a favour, you should thank the person. The best way to thank a person is taught by the Messenger of Allah 
. He advised to say the following after receiving a favor:
May Allah give you a good reward
The Messenger of Allah 
has also said the person who does not thank the people, does not thank Allah.
- Usama Ibnu Zaid  reports: The Messenger of Allah  said: "Whoever says “Jazakallahu khayran (May Allah give you a good reward)” to anyone who has done him a favor, he has thanked in the best way."
[Tirmidhi, Birr 86, (2036)]
- From Abu Hurairah : The Messenger of Allah  said: "He who does not thank people, does not thank Allah".