So, how do you deliver a eulogy?
This is a solemn occasion. It's obviously sad typically. But you are still there to give a presentation. It's not the time to get up and just start blubbering away.
It's not really helping people remember the person who just passed away any more effectively. Then it's about you if it's just you can't keep it together.
What I would recommend is focus on one or two of the qualities that people loved the most about that person. And then tell a story or two that really dramatizes that person's warmth. How they cared for people. What they contributed to the world, to their family and their friends.
Focus on that. You're not there to give the consummate biography of the whole person's life. You're not there to give an unbiased objective view of the person's life.
You're there to put a spotlight on what was special about this person. Why people loved this person and what you'll miss the most. If you do that you will give a great eulogy.
And I would recommend don't memorize it. It's already a tense situation. That tension is going to make it harder for you to recall. I wouldn't get up and read a big speech. If you want to have a few notes that's fine.
But realize this is not a test. This isn't a business PowerPoint presentation. This is a time for you to share from your heart what was special about this person. To make the other people there have fond memories.
Do that and it will be the best you can do in a tough situation.