I think the keys to this are word choice, sentence phrasing and the conviction of delivery. In other words,
Word choice - you have to use words that are not colloquial but sophisticated enough to provide some depth. However, you're not trying to show that you're a thesaurus, eg for the word "change" you could use "metamorphosis", but you could also substitute it for the word "transform". Make sure the word isn't obsolete/obscure and that its meaning is easily grasped. Keep in mind that the audience is doing nothing but listening, and they don't get to go back to check what you've already said. In short, keep most words between 1-3 syllables long and are easily understood.
Sentence phrasing - You have to ensure that you have sufficient pauses to allow the audience to keep up with you. Anything more than 2 typed A4 word document lines is too much.
Delivery - Know your speech so well that you could cut some sentences or improvise new lines and still be able to finish convincingly. For me, it helped to pretend I was acting to get over the nerves and to get rid of the drone. Some speakers tend to robotically churn out their essays, with no expression, appropriate pausing, and most illegally; without conviction. These speeches are the worst because if the speaker acts as if they don't want to be delivering their speech, that feeling translates to the audience. Act like it's normal to be using slightly sophisticated language, add some expression to your voice (speak a little slowly), stand with your back straight, face the audience (no, don't look at some point on the wall), use a clear and strong voice, and above all, BELIEVE that what you're saying is the most brilliant thing since the microwave.
If you can, make eye contact; it implies a "connection" in the sense that you are talking to a particular person, and they will more likely listen because it gives off a feeling that they should listen up.
To engage through content, try running through an example and things like "imagine.." and emphasise, emphasise, emphasise the significance of what you're saying.
Ending lines like "Harwood's poems resonate blah blah blah (rave on about its awesomeness) [include resonance and relevance/impact blah blah]. [cue very short sentence]." Work well in terms of marks.
NB: no matter how good a speaker is, if the audience doesn't want to listen, there's nothing you can do.
