Here are some tips on how to send notes of gratitude to people who sent you personal condolences:
Identify those who you will need to thank. These are the people who send cards, notes, or letters, charity donations, flowers, and other forms of assistance.
Sympathy cards which were pre-printed and which do not include personal notes need no response.
If there are a lot of people to whom you are sending thank you notes, or if the task is too daunting, ask help from other members of the family and/or your friends.
Keep the responses brief and simple.