There are several different ways to congratulate graduates or wish them well in a graduation card, notes Hallmark.com. Some simple words of congratulation include "Congratulations and BRAVO!" and the more formal "Congratulations on your well-deserved success." Words of encouragement are also appropriate to write in graduation cards and examples include "I'm sure today will be only the first of many proud, successful moments for you," and the more casual "You're going to be a star! Congratulations!"
If attending the graduation ceremony and giving the card to the graduate in person, this can be noted in the card alongside general congratulations, suggests Hallmark.com. Examples include "It's my great privilege to know you...to think about all you've achieved...and to be with you on your graduation day" and "Congratulations! It means so much to be a part of your graduation day!"
On the other hand, if attendance isn't possible, appropriate words to write in the card might include "Thinking of you with love and pride on your graduation day," or "Congratulations on your high school graduation! Wish we could be there to see it."
It is often appropriate to give words of advice in a graduation card as well. Examples include "Always remember: There's no limit to what you can do if you believe in yourself," or "Take pictures. Take your time celebrating. Take it easy for a while. Then get ready to take on the world!"