"On Writing Well", by William Zinsser, is one of the most suggested books to improve writing for nonfiction authors.

Mr. Zinsser tried (and wonderfully succeeded, IMHO) to identify the most frequent and impactful problems non-fiction writers must solve when composing their pieces. In this thread I share some notes I’ve taken reading this pragmatic book.

Good nonfiction writers create a personal connection with their readers, regardless of the subject they write about. Enthusiasm, emotions, warmth, and humanity are the fundamental forces generating this connection.

Simplicity, concision, and clarity are pillars of the personal connection between writer and readers; without them, readers have to fight against authors rather than enjoying their prose. Clear writing is hard, it requires deliberate practice to achieve it through clear thinking.

Clatter is the enemy for the nonfiction writer. Clatter is what can be simplified or deleted without affecting meaning. Analyzing and editing their pieces after the first draft, writers can avoid jargon, long words and expressions, and adverbs.

Be yourself when writing. To do that, relax and be confident. When allowed, writing in the first person can help to be natural. When forbidden (e.g. business reports, newspapers), you can write the first draft in the first person and change it during editing.