Many students, in responding to Lasswell's quote, described elements of delivery in the section on channels. The channel in communication is the "how"- how was the message structured based on the ways the audience can appreciate it. The channels are the five senses, however odd that may sound. If I tell you something, say over the phone, I using only the auditory channel. When I say it in person, you can see my body language adding a visual channel. If we shake hands, you can get a tactile impression of my sincerity and so on.
Check out the "transactional model" for a visual depiction of the communication process.
Delivery contains a variety of verbal and non-verbal elements- posture, gesture, tone, pace, volume, eye contact, proximity, object language, etc.
Think about speakers who use these elements for effective communication. Who are they? What effect does their delivery have on audiences