For Friends

• If the card is for a best friend, recall a favorite memory from another birthday and say how much you look forward to making many more memories in all of the birthdays yet to come. If you're giving the card to your friend at a birthday party, express how happy and honored you are to be included in the celebration. If the card is for a new friend, tell her that you're excited to have met and look forward to spending more time together in the future. If the card is for a friend with whom you've lost touch or are quarreling, simply mention that you're thinking of him and hope he has a wonderful day.
  
  

For Family

• If the card is for a child, mention how much you remember the very day she was born. Mention a memory or two from that day or from her birth year--perhaps what the most popular song was or who won the Superbowl.
  
  If the card is for a parent, remind him that this is his day, and you want to make sure it is the best it can be. Thank him for being your parent.
  
  If the card is to a younger sibling whose birth you remember, write about it! Get a bit sentimental--there's no better time than a birthday.
  
  If the card is for a grandparent, express how happy you are to share this part of her life with her.
  
  If the card is to a different relative, tell him how happy you are to call him "family." That statement can never be said (or heard) too many times.
  
  

For Significant Others

• Cards are a lovely keepsake in romantic relationships--something nice to tuck away in a drawer and stumble upon months later. If you are so inclined, write a love letter--a gift that's sure to be appreciated. If you'd prefer to keep it short and sweet (and avoid romantic awkwardness), try, "It's my second-favorite day of the year." (The first, of course, is your birthday!)