Every gift you receive should be acknowledged with a hand written thank you note.
Phone calls and computer generated acknowledgements are not appropriate.

Mail your thank you notes as soon as you receive a gift.
If you let wedding gifts languish for months without acknowledging them, you run the risk of either forgetting who sent what gift or insulting the sender with your tardy response.

Style

The key to thank you notes is to be sincere and specific.
Specifically name the gift, specifically name the giver and write a sentence or two about what you like about the gift and how it will fit into your new life together.

If you are writing the note prior to the wedding, mention that you look forward to seeing the guest on the wedding day.

Notes to relatives and close friends should be signed with first names only. Sign off with your full names if you're thanking people you don't know very well.

Keep Track

Buy a notebook and record a description of each gift, the date it arrived and the sender - as soon as you open it. Leave a fourth column to remind yourself when you sent a thank you note for the gift.