The hack is after you have finished writing your piece, delete the first paragraph and the last paragraph. Here is the theory behind the hack. When you are writing the first paragraph, you don't really know yet how the piece will shape up. You might be trying to overcome writer's block to get started. You haven't gotten into the true telling of you story yet. If you delete it, then you will start quicker with the story.
For the last paragraph, you are usually looking for some nifty, artificial way of summarizing and closing out the piece. This sometimes means trying too hard. By deleting the last paragraph, you avoid the common cliches at the end and have a more forceful end with the penultimate paragraph.
This hack reminded me of the classic five-paragraph essay format that many of us were taught in school. The first paragraph is your introduction with your thesis statement. The three body paragraphs are examples or points with supporting facts. The last paragraph is a re-statement of the thesis and some type of summary/closure.
Cutting the first and last paragraphs is like getting rid of the bread for a sandwich. Sure it's nice to have that bread, but it's not a must-have (and white bread is poison for a diabetic like me).
*Note: I practiced the hack on this post. This means I cut out the first paragraph where I explained where I heard about this hack. In case you are curious, I heard about it on Episode 430 of the James Altucher Show podcast titled "The Best 1 Minute Life Hacks to save time & enjoy more life."