My first paragraph is always a personable lead-in, usually with a question, and usually setting up the post. I know that I only have about 30 words to get you into it, and I cherish those 30 words.
I write with lots of chunking on posts that I want you to bookmark and revisit. Chunking in this case means doing things like putting subheaders in there.
I then make sure that the post is brief, unless I want lots of bookmarks, and then I make the post much longer. Why? Because you bookmark things that go over 500 or so words.
I finish on whatever I want you to do: either a question, or a call to action.
Key observation is that the 500 word mark represents the tipping point for ADD-based bookmarking for future reading.