Question

What is the last step in developing a speech outline?

Answer 1

Develop transitions and the conclusion.  
 
This is the last step in developing a speech outline.
 
The first is, of course, writing the introduction. Then, insert and label the subpoints. And the third is inserting and labeling supporting material.
   
For an essay or speech to be cohesively stitched, this pattern should be followed. Otherwise, the transitioning will be poor and it will hardly make sense.  

In developing a conclusion, you have to particularly summarize the gist and essence of the entire article in a striking and succinct way.