Thank you notes should be sent for gifts you receive. According to Emily Post of the Emily Post Institute, if the gift is opened in front of the giver, you can thank him or her personally. Every other person who gives you a gift this Christmas should receive a thank you note. It's a small gesture with a lot of meaning.
Store Bought Notes
There is nothing wrong with using store bought thank you note cards to express your gratitude. Be sure, however, to write a personal note mentioning the gift item specifically.
Notes from Children
Thank you notes from children do not have to be formal at all. Allow little ones to draw a picture of the gift to add to the note. If possible, include a photo of the child with the note as well. This is especially nice for people who live far away, as it allows them see how the child has grown. Older children should write a short note thanking the giver for the gift. Allow children to be creative and send artwork, stories or letters with their thank you notes.
Notes from Teens
Teens may want to send an email message rather than write out a note. Some gift givers might find this impersonal, however. Encourage your teen to write a personal note, perhaps designing it on the computer, thanking the giver for the exact gift that was given. If the gift was money, have the teen explain how the money will be used, whether for a special purchase, saved for college or in another way. If a monetary gift was spent immediately on that "had to have it" item, include a photo of the teen with the item to show just how the gift was used.
Notes from Adults
Adult thank you notes should be more formal than those from children or teens. Always be certain to mention the gift item given and express gratitude. If an item wasn't exactly what you wanted, keep in mind that it is the thought that counts, and send a sincere thank you anyway. Mentioning how special the item is always add a nice touch. For example, telling a distant aunt that the earrings she sent will go perfectly with your new dress is a nice way to personalize your thank you and make it more meaningful for the giver.