I highly recommend printing a copy of your book for editing - even just on A4 paper, as it's very difficult to edit an electronic copy. I must have re-read my own books more than fifty times, and I have been in jobs where proof-reading has been crucial, but I still missed a huge number of grammatical errors that the spell check did not pick up, or the grammar checker, but when printed on paper they leapt out of the page at me. What I did was save a copy, then worked hard on making them acceptable for paperbacks on create space. Once they were acceptable, I ordered proof copies and the errors nearly pinned me down and choked me to death! So I went back to my kindle formatted copies and made corrections.