A lot of US and UK universities have dedicated (open) websites to assist their students with academic writing - you can check those.

Here is one example: https://writing.wisc.edu/handbook/assignments/writing-an-abstract-for-your-research-paper/

Same with academic publishers:

https://www.journals.elsevier.com/social-sciences-and-humanities-open/policies-and-guidelines/how-to-write-a-great-abstract-for-your-academic-manuscript