I have been in the publishing business for 12 years.
The best way of passing the SmashWords formatting rules and having a good looking ebook is to FORMAT IT DIRECTLY IN THE FINAL SMASHWORDS FORMAT (epub) avoding the Word conversions.
Formatting is an art and it must be done depending on its kind. It is not the same a novel than a recipe book.
To achieve the best results I format the book manually, and of course adding the table of contents, the metadata, and the cover you have chosen. I will deliver it to you ready to be published in SmashWords, and if you need a cover I will include it in my service as well.
As a general rule I will format 10-30 pages per Gig but that depends a lot on the complexity of the formatting to be done, so, send me the book before ordering to make you my best offer.