You can only land in one airport

My favourite analogy for a speech or a presentation is the aeroplane journey.
It nicely sums up the simple structure of:
beginning, middle and end, as:
take-off, flight and landing.

The analogy holds very well because regardless of whether it is a short journey or a long-haul flight, the 2 moments that stick most in the memory are the start and the finish.

The analogy also works well as, like the middle of a speech, the middle the flight may need to have a degree of flexibility:
weather conditions may cause the pilot to rise to a different altitude; the plane may go off course, but if there is a clear landing destination, the plane can readjust or make up time. 
It can even stack in a holding pattern before landing!
All metaphorical skills adopted by a good speaker.

The plane can even be off course for most of the flight, but as long as continues to readjust it will still make its destination. 
And I am sure we have heard speeches that have wandered all over the place, but as long as they reach a suitable destination, we are happy:  if they just fall apart and get lost we are not.

For me however the key value of the airplane analogy is the fact that:
you can only land in one airport at a time!
This is very important for presenters to bear in mind, as often we have so much to say we want to make lots of points.  So 'Yes' - we may be able to stop off at a few key points on the way, but in the end there can only be one final destination.

So for example, I am going to deliver my beliefs on what makes a successful life.

However my considered conclusion at the end of the presentation is that
Success is a combination of things: working hard, good relationships and a positive attitude.
The problem here is that if we assume (and we do) that audiences are easily confused, it would be better for me to lead them to one overriding conclusion with one clear message.
But all 3 points are so important!
Then we just need to prioritise.
The conclusion to my presentation on Success can still end with a reference to all three elements; however because I realise I can only land in one airport, I may choose to finish with either:

'The key to success comes down to a combination of things:
working hard, good relationships but above all else you must have a positive attitude.'

or
'The key to success comes down to a combination of things:
good relationships, a positive attitude, but above all else you must be willing to work hard.'

or
'The key to success comes down to a combination of things:
working hard, a positive attitude, but above all else you must have good relationships.'

In each case I have chosen to prioritise just one key point.

So don't risk confusing your students or your audience with too many messages.
Prioritise!
Stop off on the way if you wish, but make sure you only have one clear final destination.