Agree with 10 books at a time.
Sometimes, if it's possible, have the students work on loose sheets, which you then mark and return to them for sticking into their books. I find a pile of sheets less intimidating to mark than a pile of books. Also the sticking in time during the lesson can also be used as time for the students to read your feedback and ask for explanation of any comment they don't understand.
Get a "verbal feedback given" stamp and then have the student write underneath your stamp a concise summary of what you advised them - evidence that they have understand what you said.
Similarly, have the students tick your written feedback or do something else (e.g. copy spelling corrections) to show that they have read it.
Consider getting other stamps or stickers too - look on Amazon, etc. Or make your own stickers.
Also this may sound obvious but do make sure you know your school's marking policy for each subject (if there is one!) Otherwise you may end up doing "too much" marking, or putting in a huge amount of effort that isn't recognised or is even criticised because you're not doing one of the required things.
Make sure the students give you their books open at the page for marking rather than a closed book. This will save you time.
Consider having a checklist on the classroom wall or stuck into the book of things that the students should check before handing in their book (e.g. date, title, capital letters, full stops, etc.). This will save you time writing the same comment over and over again (e.g. "Where is the date?")