As a Celebrant, I studied ritual and ceremony and learned to craft funeral ceremonies.
To honor the person who has just died, begin with the facts. He was born in (town) on (birthdate), where he lived for (number of years). He went on to study (subject) at (college, trade school) or, He went on to make a living at (occupation or trade).
Then continue, But the facts of (Name)'s life don't begin to tell the whole story. He was a (name some qualities) man. He loved his (family, country, work). And he could always be counted on to (some way he was dependable).
Then tell a brief story or two to illustrate the kind of person he was. If you have a personal experience, write about it. It doesn't have to be perfect. Write it the way you'd tell it if you were just talking to one person. You can be sure it will touch your listeners.
If you don't have a particular story in mind, talk with family members and friends. Take notes. Don't be afraid to tell a funny story, as long as it isn't embarrassing to the family.
You can also look at photo albums, letters, emails, even invoices or bills to jog your memory or give you some clues as to what to write about.
End by saying that you'll always remember the qualities that your story or stories illustrated (his kindness, dependability, humor) and that he will be missed.