I have become totally convinced that the human eye cannot catch everything while staring at the computer screen. And after rereading material so many times, the brain gets imprinted, and can't spot the errors.
When using the CreateSpace system, after all your files are set, you order a proof copy sent. This is where if you're anxious, it can start to get costly, depending on the speed of shipping you choose.
You're only paying print costs, which depend on the number of pages and size of your book, and then you have a choice of three shipping speeds. Nick and I, like most expectant parents, couldn't wait and paid top dollar. They give you estimated arrival dates, but our experience is that the books come a lot faster than they list, so paying the extra for top speed wasn't really necessary.
With printed book finally in hand and you snuggle up on the porch to read, be prepared to be aghast. Typo typo typo. Have red editing pen by your side.
We've tried on each book to have at least 5 sets of eyes go through them, before we even printed out the last draft, enlisting the aid of a professional editor friend, and then other writers, as well as simply avid readers.
Each person will have different suggestions, often vital. We've sent the material over the computer, but for future books, I think I'd probably order 5 proofs and have them shipped directly, and have everyone read them from paper copy, and just jot down page number and paragraphs.
Then the revised files go back to CreateSpace, and you order one more proof, wait for that to come in... and finally approve it for publication.
You can jump the gun on that one, if you're positive it's clean copy, and just approve it before you get the book. We did... and um... that was inexperience showing.
The first readers, (friends and family), started mentioning wee little things, (I think I made typos while making the edits! Oh NO!) and we ended up halting production a couple different times. Revising, getting yet another proof... At least with CreateSpace, we have that control.
CreateSpace is tied with Amazon, though you don't have to list it there. If you have Amazon reviews of your book already up, and you halt production, you'll lose those reviews and have to go around and ask people to do it again. (A very uncomfortable thing to do. Even asking the first time, is hard for us.)
One thing to remember about self-publishing vs traditional, is you lack an editing department and a proofreading department for pre-production. (Not to mention lacking a marketing department for post-production!) If you can't afford hiring one of the 'book doctors' you see advertised all over, be prepared for a lot of effort.
So one of the biggest things we've learned around this whole process is "Take your time and don't trust computer proofing!"