Ways to wish a happy birthday to someone turning 90 include throwing a birthday party in a location that is close to the celebrant and making a table of pictures of the celebrant throughout the years. It's also fun to display newspaper articles from her day of birth.
A slideshow featuring the guest of honor is also a neat way to show that she is loved and has lived a long, eventful life. It is good to pick a party theme that is near and dear to the celebrant's heart, such as a luau if the person enjoys trips to Hawaii or a cowboy theme if she enjoys western films. If the guest of honor enjoys a laugh at her own expense, a roast is a lively way to make a 90th birthday memorable.