This is Avinash Dixit advice on keeping research simple and papers short:
"Over the last two decades the average length of economics papers has increased quite a lot. Advances in word-processing technology have greatly reduced the cost of producing words, but not the cost of producing ideas, with the result economists should expect -- massive substitution.
My ideal is neatly captured in a question Frank Hahn posed to an author. As an editor of the Review of Economic Studies, Hahn asked the author to cut down his paper from 40 pages to its essential core of three pages. When the author wrote a long and indignant letter, Hahn responded in two sentences: "Crick and Watson described the structure of DNA in three pages. Kindly explain why your idea deserves more space."
I have saved for the end the most important lesson I have learned from my experience, and which I believe has very general validity. Maintain a youthful sense of freedom to choose problems and the directions of work on them. Imagine yourself at twenty-three, not yet labeled or confined to a particular "field," and not yet pressured to produce something quickly for the approaching tenure review. Try to preserve this mental frame in your research, even as your body, and the part of your mind dealing with other matters, continue to age and decay.
Unfortunately, in the US most academics do not regain this freedom until they are thirty-five, by which time it is too late for many of them to be twenty-three. Their research brain is beyond rejuvenation, and it is time for them to leave the research frontier and join the conference circuit or the policy community."