Which tip permanently improved your writing skills?

The two tips that have worked wonders in readability and credibility for all sorts of people (even authors) in my 40+ years in publications work are these:—

20–25 words per sentence and 2–4 sentences per paragraph — or 40–100 words per paragraph (median 70 words). This is plenty of legroom for obeying one of the tenets of good writing: vary your sentence structures.

One-shot-through sentences in the active voice.

Dummy text to show wordcount:—

20 words:—

Lorem ipsum dolor sit amet consectetur adipiscing elit ulla mollis blandit justo nec iaculis dolor lareet ac pellentesque suscipit at.

40 words:—

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque eget lobortis ante. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vivamus et risus tortor. Vivamus non erat ut libero ultrices ornare. Nulla ac arcu et.

70 words:—

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas nec sem ornare, lobortis felis nec, pretium urna. Quisque ut mollis lorem, non elementum lacus. Ut egestas tellus elementum odio ultrices, sit amet auctor nibh euismod. Mauris eget fermentum ipsum. Aenean semper libero eu molestie ullamcorper. Sed et enim a nisi lobortis consequat vel et mi. Donec in eros eu nunc rutrum condimentum. Integer congue leo lacinia elit bibendum convallis nam.

ONE SHOT THROUGH

These are definitely not a “one-shot-through” sentences (real-life examples):—

The proposed bill, if implemented, whose effect is expected to increase the rate of inflation within 13 weeks, has garnered criticism immediately for its proposer from across the political spectrum. (30 words)

The police, who are on the hunt for the killer of a police officer who was killed from being stabbed in her own home in northwest London, are looking for a man, who was seen by the police officer’s neighbours to have been wearing a white top and running away from the crime scene. (54 words)

But these are (real-life amendments):—

The proposed law and its proposer have drawn fire from all political quarters since it would likely raise inflation within 13 weeks of being in force (26 words)

Police hunting for the killer of a policewoman stabbed at her northwest London home are looking for a man in a white top seen running away from the scene by neighbours. (31 words)

Yer pays yer money, yer picks yer goods.