Most people can NOT edit their own work very well.
I would imagine that some professional writers who are also English professors might have that capability.
But the issue is not SPAG or education, it is psychological as it is too easy to keep overlooking the same mistake that was made when you wrote it and reread it during the ...
Is it possible to teach yourself how to line edit and copy edit if you are the writer?
I'd say "yes" and "no".
It is of course possible that you can teach yourself to edit. It will probably be harder than if you found some school or teacher, but not impossible.
However, should you edit your own work? Sandra Wendel suggests that "......
Line editing; TBH, I didn't know what this meant and had to do a quick google search to figure out what you meant. So I'm probably a bit off, but I think I'm close enough to still be of some help. Line editing is mainly making sure you are using your words to their maximum potential, and can be very impactful on your works. This is probably going to be one ...
According to the APA style guide, "A subtitle should be separated using a colon or em dash (i.e., — and not the shorter - en dash) and then a single space (i.e., Title: Subtitle OR Title — Subtitle)."
Personally, I find the Oxford Style Guide recommendation of an en-dash far more aesthetically pleasing.