I use this simple strategy for my abstract writing and it has been helpful.
* A general knowledge about the area
* Sentence on problem statement or gap the study intends to address in literature
*Objective of the study
* Statement on the method adopted and analysis procedure.
* Major findings/results from the study
* Key message the study conveys. I call this a punch line statement. Others may write about a key recommendation or practice and theoretical implication of the study results.
initially choose the topic which you need to write followed by its overall content in two lines and its important why you have choosen the topic its importance and your outcome
The guidance/discussions as per the following publications/link should be helpful:
Andrade, C. (2011) How to write a good abstract for a scientific paper or conference presentation, Indian Journal of Psychiatry, 53, 2, pp. 172-175.
Bavdekar, S. B. and Gogtay, N. J. (2015) Writing an Abstract for a Research Manuscript: Providing an Honest, Succinct and Complete Summary, The Journal of the Association of Physicians of India, 63, 12, pp. 64-67.
Day, R. A. (1998) How to Write and Publish a Scientific Paper. 5th edn. Phoenix, Arizona: The Oryx Press. (See: How to prepare the abstract).
Mack, C. A. (2012) Editorial - How to write a good scientific paper: title, abstract, and keywords, Journal of Micro/Nanolithography, MEMS, and MOEMS, 11, 2, pp. 1-4.
Thrower, P. A. (2007) Editorial: Writing a scientific paper: I. Titles and abstracts, Carbon, 45, 11, pp. 2143-2144.
What is the difference between "the Abstract" and " the conclusion" ?: https://www.researchgate.net/post/what_is_the_difference_between_the_Abstract_and_the_conclusion
I have little knowledge on other disciplines, especially the physical sciences. But the format I shared with you is applicable in most social science disciplines.