What you write in the card that accompanies your wedding gift can have as much or more of an impact on the couple than the gift itself. Writing a simple "Congratulations!" or "Best wishes!" is one way to approach the card, but it doesn't offer anything personal or specific to the couple.
Include a specific memory of the couple in your wedding congratulation message. This helps to personalise the card and make it special because it came from you. Think back to the first time you interacted with the couple. For example, if you all went to dinner for the first time several years ago, write about your first impressions of the new partner and how happy you are to see their relationship grow into a marriage.
Include a titbit of information about yourself that ties in with the wedding. Though this should be done carefully so as not to focus too much attention on you, it can add a sentimental touch to your message. If you've been married for 25 years, write that you hope the new couple's marriage lasts at least twice as long as yours. If you've recently become married, tell the couple how happy you are to share in this life milestone with them.
Look Ahead to the Future
Mention something about the couple's life together and your hopes for their future. For example, you could write that you hope they dance at their grandchildren's weddings or that you look forward to receiving an invitation for their silver and golden anniversary parties. Saying something that alludes to a long, happy marriage shows the couple that you are supportive of their union and wish them the best as they embark on life together.
Humour should be used cautiously in wedding-card messages, but it can be executed in a tasteful manner. Saying something like, "I hope you enjoy your time together and enjoy indulging in your new life together--just don't forget about me!" or "I wish for you to experience half of all the wonderful things in life (the other half is for me)." This type of sweet humour is sure to put a smile on the new couple's faces.