How to most easily convert a PDF to epub - which is a money-maker

Time is money. You can't get it back, so you have to invest it carefully.

If you're like me, and have been publishing books into PDF format for years, it may be more difficult finding the original documents than thought.
On top of this, converting anything to ebook epub files is a rather tedious task of finding and correcting errors so they will be accepted.
Accidentally, I found a sequence which tends to create a very good ebook every time:

1. Start with your PDF and make sure it isn't copy protected.

2. Open this with a full version of Adobe Acrobat (I'm still using 6 myself, though later versions should work fine.)

3. Save as HTML 3.2

4. Open that HTML file in Open Office (Libre Office) and tweak it per Smashwords Style Guide to get rid of extra carriage returns (paragraphs) and tweak the title page, etc. 

5. The first time you save it, you'll have the option to save it as .ODT - take it.

6. Get a plug-in/addon called writer2epub - this will convert your OpenOffice document to an epub and allow you to add in a nice cover graphic and ensure that the author, title, publisher, description, and everything else is nice. 

7. Then save it as epub and open it up in Sigil.

8. Run an "epubcheck" with Sigil and then fix anything which then may come up. What I've found is that this sequence saves a file usually with no errors. 

Now you're ready to upload it to Lulu.com or Amazon's Kindle Direct program.
And this saves me tons of time. It's also a way to convert any other PDF you find so you can carry it around with you on your tablet or smartphone. Because PDF files don't read well on these devices, particularly when you have a small screen.
Now, if you don't have a snazzy cover picture, you simply open it up later in Calibre and tweak. This will also enable you to convert it to .mobi format so you can open it up in your Kindle. As well, Calibre will run on your own computer as a server, so will enable any wifi-enabled ocmputing device (smartphone, too) to download your ebooks to anything you want them on.
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A discussion of distributors is in order.
Amazon's Kindle program has a 70% market share and is as closed down as they can make it. They don't accept PLR but will accept Public Domain if you tweak it per their instructions (like adding in 10 images.)
Smashwords gives you access to basically every possible distributor out there and every possible platform. They don't accept public domain or PLR - and will cancel your account without warning if you are caught publishing the latter.
Lulu.com publishes to Barnes & Noble, as well as Apple's iBookstore - and will take public domain and PLR - providing you've edited it properly to make it something new and valuable to readers.
While Smashwords pretty much only accepts Word .doc's - (you can save Open Office docs in Word format), they will generate all these versions for you once you get through their "meatgrinder" program. That would be porting to them after step 5 above. I haven't taken this step yet - it's been the hell I've been going though to find and republish my ebooks late into last night which prompted this early morning post for you... But I'll let you know when I do.
Both Lulu and Kindle will also take Word docs. But when you get a rejection, it's a mess to fix - just like Smashwords. They'll tell you the error, but you have to find and correct it in the underlying HTML/XML below the Word doc.
The sequence above gives clean copy routinely, so it's my sequence of choice right now. (I may even publish to PDF out of OpenOffice - which does this natively, preserving all links - in order to clean up older versions.)
By publishing your book to hardcopy as well as an ebook, you boost both sales. I prefer Lulu than Amazon's CreateSpace function - simply because Lulu will publish to Amazon, Barnes & Noble, plus a host of other retailers. The world may seem to give Amazon a lot of attention, but doesn't revolve around them.
Your publishing sequence
First publish as an epub and get it on Amazon. Publish that same epub to Lulu but distribute it only if you used public domain or PLR as part of it. Original fiction is safest... Take the Word doc and publish to Smashwords (add in their "smashwords edition" text and disclaimer as they ask.) That takes care of all bases for ebooks.
Next publish a hardcopy version (all "gussied-up" with headers and footers and indexes and such) via Lulu. I upload them as PDF's generated out of Open Office. You'll want to format it for probably 7x9 size, which is most common for books. Then you can take that PDF and generate several print editions (both paperback and hardback, as well as PDF itself for sale on Lulu.) - so this is another time-saver. And while you have that copy open in OpenOffice, you can reformat it to various sizes for other formats Lulu offers - just re-output to PDF and upload. Yes, you will have to tweak covers - and I suggest you build your covers in OpenOffice Draw program - since it will save to JPG, but builds in SVG, so your fonts can be scaled more easily. But some like Photoshop and others like Gimp - whatever stirs your kettle.
And while you are doing this, you are busy with your product release sequence (launch) but that is another topic for another day.
Suffice for right now is that you get all your books up and published  to as many of these as possible - ebooks first as they show up faster for sale - and then follow with hardcopy versions.
Yes, there are many more details to this. Instead of doing it all here, I owe you an (e)book on the topic.
You'll probably find I will be giving the tips away right here - so stay tuned...