Generally speaking, usage is “the way in which a word or phrase is normally and correctly used.”
For example, in American English, ‘decision’ is commonly used in the form ‘make a decision’
whereas in British English, ‘take a decision’ is more common usage.
Usage is a constantly changing phenomenon.
Learn to use google’s Ngram Viewer, link below…

Word questions
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USAGE and word choice
University of Victoria (great campus!) usage guide

Cohesion devices: logical connectors a.k.a. signposts a.k.a. connectives,
BTW: explore this site – it contains good things but the navigation doesn’t tell you much.

USAGE and style guides

Garner’s Modern English Usage introduced here

The Economist style guide for seven pounds is indispensable for GRIPS students.
The Economist magazine also has a free style guide; although it is simple, it is solid.

The Asian Development Bank Institute has its own style guide and style notes:

Grammar Girl web site and podcasts (despite the name, a serious contemporary usage resource)
MIT’s ComDor Editorial Style Guide
Writing Technical Articles
Technical Writing
Strunk and White’s The Elements of Style online
The Coventry University Harvard Reference Style is here
Journalistic style:  the 4-box system
Google ngrams: a pretty cool tool:

USAGE: Concordance
1. Fantastic! Three great concordance samplers which can access the biggest and most famous corpuses (including the British National Corpus) are:
Brigham Young University’s concordancer
Sketch Engine has access to a number of corpuses (corpi)

Perhaps usefully, the British Academic Written English Corpus is a record of proficient university-level student writing at the turn of the 21st century

2. Make your own concordance! Laurence Antony at Waseda  University made Antconc, a free software for making your own concordance.

3. Google can be a simple concordancer too: