Never, ever agonise over the use of ‘etc’ or ‘et cetera’ (Latin for ‘other things’). Just don’t use it. What it means is either:
a/ I can’t think of sufficient examples with which to illustrate this point.
b/ There are no further examples with which to illustrate this point, though I wish there were because it would make the point stronger.
Here are a few ‘other things’ which don’t fit under any other specific title, but are worth noting:
Using quotes by famous people in marketing copy
“It’s the last resort of the bankrupt copywriter.”
Giles White, 2014
Everything in the correct order
When using quotes, why lead with the quote, not the person? After all, 90% of the significance of the quote resides in the person saying it. You are more likely to understand the quote immediately if you already know who is saying it and in what context they said it.
And, to give this principle* a slightly wider application: make sure you give the reader the information they need in the order that enables them to get your point, with the least amount of effort.
* Useful mnemonic
Principle or principal.
Well-principled (a person with principles)
The principality (he’s principal of a principality)
…and one more:
Stationery or stationary.
Letter (with ‘e’)
Parked car (with ‘a’)