A great way to start would be think of the person or people who the note is intened for. Second did they say do or give you something or do they just mean something to you. There are many different ways you can approach this. This just depends on how much or how little time you would like to spend on each note. For example my daughters baby shower I had made little pink bows out of construction paper and wrote a little saying and thanking them for their gift. Or for example when my husbands aunt gave a baby luncheon for my son. The only reason for the second baby shower was because my son is the only boy to carry on his last name. The thank you notes we had written were actually cards that had already said thank you on the front. But they were blank on the inside. So we had decided to write what we appreciated and were thankfull for to the person the card was intened for. Just have fun and enjoy writting something that comes from the heart. Not everything has to so serious all the time. That is unless the situation calls for seriousness.