By which I mean, how do you choose where to define the limits of a given topic? I'm somebody who's gotten into writing and research lately, mainly relating to broad twentieth century political-economic history. The essays generally hover at around 3000-4000 words. One thing I've been wondering is how do more experienced researchers and essayists know when they've compiled "enough" sources? Or at the very least, how do they know when they don't have to corroborate certain sub-narratives within their history (like for instance talking about the centrality of housing in the Civil Rights movement)? Since, if you try to explain and corroborate everything, then your essay will probably never get to the point it's trying to make; after all, an essay that does more explaining than arguing is hardly an argumentative essay.
This is a question important to me as somebody who aims to become a better researcher and writer. There's been a renaissance in Marxist studies and so I wish to contribute to that by presenting Marx's insights in synthesis with my research in the clearest way possible to the layman. But striking the right balance between exposition and argument is crucial in presenting this information as clearly as I can. So I'm interested in your thoughts on the matter. Thank you!
Main tip is to know your audience and adapt accordingly. Relegate technical details or tangential points to Remarks, Footnotes and Appendices.
This can be very difficult and often times it's very useful to have another person take a look at the essay before publication as they can usually tell you when you're going too far into the weeds or where things need to be clarified. When I write there's often many moving pieces and connections, so I have these problems as well. When you're done with a draft, it's important to go back and remove stuff that's only tangential to your final thesis.