1) I have received print submissions without PAGE NUMBERS (not often, but still, this should never happen).
2) I have increasingly been the recipient of manuscripts that don't underline words meant to be italicized in the story's final, printed form. The reason editors/copy editors/and whoever does the production on a mss need to see underlines is that some typefaces don't show italics very well, and even if they did--it's quicker to "see" underline than italics
3)I have been receiving mss without anything indicating space breaks. What happened to ###? I'm in the middle of reading a printout that seemed to be missing at least two pages because there were no transitions...When I checked the efile, lo and behold, the sentence breaks were in different places so I could actually see that there were supposed to be space breaks. Writers--new and pro--please please show your space breaks by putting in hash marks.
4) Paragraphing--before online publishing, paragraphing was shown by indenting margins...Guess what, folks? Most publishing (especially of books) is still print, which means that paragraphs are indented.