K. LambMy level of knowledge is limited to the two books I have formatted to date. I think it is important for any prospective author to research this topic before trying to format a book, even if they contract this out to someone else. There is a wealth of information available on the internet and on Amazon.
If you are a publishing a book then I'm going to assume you are also an avid reader. Go to your library and start looking at the books you own. How do they look compared to the one you formatted? Here is one rookie mistake: Did you indent the first line in a new chapter? You did? Oops--that shouldn't be indented! What about widow-orphan lines? Do you know what those little buggers are? If not, it is time to do some more research! I read an excellent article back when I was researching, I wish I could remember where, about some of the most common mistakes made by new authors. I'll have to go through some of my research articles to see if I can locate it. It pinpointed out how to easily tell the difference between a professionally formatted book and one done by an inexperienced amateur.
Then there is also the consideration of the font you will use. Again, there was a great article I read chock-full of information about fonts, their sizes, what types for different genres, book sizes, etc. All of this is invaluable information to know prior to beginning the formatting process.
Now all of this is based on formatting a print version of your book. Formatting an ebook is a whole other process. As I said before, I was responsible for formatting both of my books. I did them both in print and on the Kindle platform. Did I make errors? I'm sure I did! Will I get better as I move forward? I certainly hope so as I continue to learn and gain experience. The most important thing is start off putting your best foot forward. After all, you don't want to be the one that someone can easily pinpoint as an inexperienced amateur.