I've seen a lot of graduation speeches throughout my educational experience. Some were genuinely inspiring and made me feel happy and confident about moving on. Others made me laugh and remember the good times. And some were just plain annoying. The point is, the art of writing an inspiring graduation speech is complex. Here are my observations about how to write a truly inspiring graduation speech:
Everyone will give different descriptions of what they find inspiring, but most people can agree that someone or something that is inspiring doesn't go around boasting that he, she or it is inspiring. Try to avoid using the words "inspiring," "empowered," or any other word that generally denotes the same sort of vague concept of being better than most people in some complex, difficult to describe way. It's pretty redundant, and most graduating classes have heard the whole "you are empowered and can do anything you want, you are incredibly inspiring and nothing will stand it your way" speech countless times throughout the course of their life (even if they're just graduating from middle school). It was kind of sweet the first time, but it gets old. Fast.
The best way to be inspiring is to be modest about it. To quote the Tao, "When you are content to be simply yourself and don't compare or compete, everybody will respect you." The same goes for gradation speeches; a personal story of how the group has inspired you in simple, unique ways is more likely to leave the audience feeling good than talking about how they're going to take over the world because they're empowered men and women. Quite frankly, that's a little too scary, even if the ball is in my court and I am, in fact, the one conquering the world with my empowerment. Stick to the everyday, and for goodness sake, don't scare the audience!
That being said, don't go completely everyday and base the whole speech on inside jokes. Parents and relatives who are unfamiliar with the everyday events in a college, high school or middle school just aren't going to understand why it was so funny that Timmy dropped the pencils all over the floor right when Mrs. Roberts started speaking. Yeah, we all had a good laugh over it. But it's irrelevant and most of us just want to get out of here before midnight. Anecdotes that directly relate to the rest of the speech are fine, but save the inside jokes for the after-party.
The speeches I've found the most inspiring have used quotes that are complex and universal in their simplicity. The Tao or other Eastern philosophical works are excellent places to find these, as well as many of the specialty books of quotes that they sell at the front of Barnes and Noble. "Carpe Diem" poems are very appropriate to graduations, but don't go overboard with them because a lot of students have heard them ad nauseam at other graduations. You should also keep in mind the personalities and experiences of the graduating class as a whole; if there is a quote or song that is especially relevant both to them and the event, consider incorporating it into the speech. It gives a personal touch that can be quite poignant if done well.
Overall, a truly inspiring graduation speech should be genuine. If you want to express how much you care about the graduating class and how you sincerely wish them the best in all that they do, say it just like that. Don't go crazy making it sound "smart" by adding big words (because no one wants to listen to a pretentious speech), or adding in every little detail about what happened in [insert school graduating from] (because we spent four years there already and we don't need to relive it again). Just say, in your most natural way, how the class has influenced you and how you want them to succeed. Unless, of course, you don't. But then again, you wouldn't be giving the speech if you didn't.
Writing an inspiring graduation speech is all about balance; if you find the right combination of personalized stories, genuine feeling, relevant quotes and encouraging the graduating class to succeed, you should be able to write a great graduation speech that the graduating class will remember and be able to think back on fondly. Or maybe they won't end up remembering the speech, but remembering the overall feeling. Or they could just flat-out not remember it. Whatever ends up being the ultimate solution, I can advise you that the best strategy is to just be yourself; I haven't forgotten a genuinely inspiring speech yet.