Creating an outline can have many benefits. First of all, it helps you -as the writer - concentrate on your writing process. Secondly, it gives a significant amount of organization and structure to your written AND presented eulogy. Lastly, it allows you to break your writing process into clumps so you'll never forget to include all the critical tidbits.
The first step is to decide the tone of your eulogy. How well do you know the deceased person? Were you a close friend or a distant relative? What exact message do you want to exhibit? Do you want to include any personalization or metaphor?
Once decided, you can then move onward onto details. Think of every detail related to the tone you've decided on. One of the best ways to think of details is through the process of brainstorming.
A good and honest way to think of details is to list the person's name on a piece of paper. What all do you think of when you think of them? How did they contribute to the world? How did their lives cross with yours?
Lastly, now that you have your main points down, go back and elaborate on them. Do you have any unique stories to tell? How did it affect you? How can you make this story concrete so it affects the audience and helps them recollect the deceased? Remember to break each point down further into specific nuggets of detailed, entertaining information. People love concrete stories and specific examples. Strive to include unique things that the audience can recollect and/or remember this person by. Speak from your heart... you'll own the audience