TL;DR subtitle: I attended a self-publishing seminar at the SFWA Weekend in June, and I learned a bunch o' useful stuff. 

Pump up your book's appeal. But not with these.

The first session covered formatting tips for each of the main parts of an ebook. There were digressions into print formatting as well. Most of the ebook tips were based on one fundamental point: ebooks aren't books. They attempt to replicate the feel and look, but they offer "unique challenges and opportunities."

Cover
I could spend a whole post on covers alone. Later. The teaser: your graphic should look as tempting on screen at 1" as it does at 6" or on a physical book. Your cover won't sell a book, but it can lose you sales. 

Front matter This = everything in the book before the story.
Cover page, copyright/cataloging data, tables of contents, dedications, acknowledgements, introductions, teasers, reviews, artwork, and secondary title pages. Not all books have all these feature, obviously. All have some of them.
Books: readers who want to browse simply page past it all.
Ebook: online sampling only shows the first 10-20% of the interior. If you have a lot of front matter, your reader only gets a few pages of story at best. I've seen books where barely two pages of a novel were visible.
Book suggestions: 
if you want a book to attract readers, put all the work into the front matter a traditional publisher would. Check books of similar subjects, and format your book accordingly. Appearance matters. Make your book look and feel "real."
Ebook Suggestions: 
1. Lose the table of contents. E-readers generate them automatically.
2. Move dedications and all other non-essential material to the back of the book.  Yes, even maps. Especially maps. A cover page & copyright/catalog info are all you need before the story. Pump up the sample size for all it's worth. Samples hook readers. It's that simple.
Common to both formats:
Make sure your copyright page has all the information a library would need to classify your book. (Another topic that may take up its own post.)

Body The text of the story. Prologue, chapters, etc.
Books: A lot of tiny details make a huge difference in a reader's impression of your story. They're points most readers don't consciously notice (and some swear they don't care, but overall sales patterns say otherwise) Once again: a book should look like a book and read like a book.
Ebook:  The online ebook converters for most of sales channels handle most of these tiny details for ebooks automatically. Huzzah! They don't do them all, however, and they don't necessarily do them well. 
Book Suggestions:
At a minimum, your pages should have running headers and footers alternating title and author at the top, page numbers on each page of the story and only within the story, dropped capital letters and decorations at the beginnings of chapters...again, it should have all the real book flourishes. Yes, font matters.
Ebook Suggestions:
1. Format your text like a book. Use indents to begin paragraphs, not line breaks. Always. (It went without saying for print books.) Don't worry about font, as the reader can choose their own--but don't use lots of different fonts.
2. Do all you can to make your titles and chapters "pop" for readers. If you can add graphics to your chapter headers, that's a great start. Ditto for using dropped capitals and other decorative tidbits that make pages pretty.
3. If you can create an ebook format yourself and upload it, you can customize presentation to your heart's content. That requires a whole 'nother skillset and tool kit though, and it's not for everyone. (Not for me!)

Back matter This = everything after the story, and it's where ebooks can really outshine print books.
Books: The costs of printing and the need to have a certain page count for balanced printing drastically limits the amount of space you can afford to give all the extra bits beyond a story. 
Ebook: Only pixels die for your extras, and the download costs are minimal. The sky is the limit. Add All The Things
Ebook Suggestions:
1. Immediately after "The End," lead right into an excerpt from the next book you want the reader to try. Not the first chapter! That's in the look-inside feature every sales channel has now. Pull a short dramatic scene, an action sequence or something funny from later in the story. No spoilers!