I mean, you already have a blog post you want to write. Can't you just dive in and write it? Why all the pomp and circumstance with this dag-blasted introduction!?
Can't get started writing? Just start. Anywhere. Forget writing a brilliant introduction. Trying to be brilliant -- indeed TRYING to write -- will block you. Write whatever's in your head.
I like to make a list of ideas before I start, but sometimes I just start writing. All writing's discovery.
Tip: use a timer. Set it for ten minutes. Write.
When the timer sounds, you've got something you can mould into shape.
Write your introduction and conclusion once you've written a first draft.
Another tip. If you're writing a book, start anywhere. You may find yourself deleting the first chapter once you've written your first draft, so don't sweat it. Write.