When estimating the number of pages or the number of months it will take you to finish the manuscript, don't give a range, such as 200 to 250 pages or six to nine months. Avoid the words about, tentatively, approximately, or estimated. Unless you have a finished manuscript, editors know you are guesstimating abuot time and length. Be specific, even though you can't be sure. This adds authority and credibility to your guesstimates.