I do a lot of work with formatting and proofreading manuscripts for print or ebook, and find the same problems cropping up again and again, so here’s some suggestions to make life easier for yourself and for your formatter:
Don’t get too fancy with your formatting. Times New Roman 12pt is straightforward. Paragraphs should be indicated with either automatic indenting or automatic spacing between – this should be done via the Styles function, preferably, as any change that overrides the styles function could cause issues throughout the file. Using tabs or spaces to indent, or leaving blank lines between paragraphs, is not a good idea. If you don’t know how to indent/space automatically, your best option is to leave the text un-indented and let your formatter deal with it.
Be careful with versions. Make sure your file versions are clearly labelled, and make sure you are sending the right version to your formatter/proofreader. And don’t keep sending updates once you’ve sent them a file! If they have to start all over again with a new version you’re increasing the time taken and almost certainly increasing the cost involved.
Give any changes and respond to any queries as clearly as you can. Gather all corrections together and provide them in a single clear list, with indication as to what is wrong and how it needs to be put right. Text to search on is always useful.