Writing a speech is an art form. And like any good artist, you need to nail the basics first, follow a few tried and true guidelines, and then infuse your personality and emotions into your speech in order to make it yours.
That’s what separates good artists from great artists. Good artists are good, but their work is forgettable. Great artists inspire and move you, and that’s what makes them easy to remember. It’s all in the way you make people feel, and since this is a sentimental subject for everyone, that won’t be too hard to pull off if you just speak from the heart.