These are general tips based on my experience as a Scientific Editor and are not meant to reflect policy or practice at any particular journal.
This is the published abstract for one of my papers back when I was in the lab. The next few slides will take you through my thinking about how I would revise the abstract for clarity and accuracy.

Some tips for preparing your manuscripts: Selecting a journal, titles & abstracts, cover letters

By Brian Plosky

Link to Manscript

DOI

Questions: all,

It is great to try to avoid jargon, but in reality, it is hard to get away from.  I think that it depends on your intended audience.  If you are aiming for a general interest journal and trying to make a broad point, then use less jargon.  If your message is intended for a specific field, then you could use more jargon.

If you have specific details, you can mention names, amount of overlap, where you think the paper was submitted, and when you think it was submitted.  Things can get a little awkward if you tell us how you found out (e.g. somebody reviewing the competing paper told you).  We also don't need to know things like why you think your paper is better since we don't have the other for comparison

It is probably less important than the informtation in the abstract and the paper itself.  Styles have changed over the years.  People used to publish papers with titles like "On the enzymology of ...".  Personally, I prefer knowing what the enzyme does.  Sometimes, it can be hard to capture the take home message of a paper in a title, so soemthing general can be appropriate.  Also, some scientists prefer to be cautious and declaritive titles don't leave a lot of room for caution.