I am really just starting to fall in love with the 1-page format, so I am still finding my way when it comes to text economy.
My big thing I am hammering as I iterate on them is to be wordy when it makes the most impact to be wordy and back off the rest of the time. Figure out where you just need to use some text.
I am really trying to get better about using tables, grey boxes and other layout tricks to getting the most out of the space you have on a single page.
My real concern right now as I am wrapping up my first adventure path of one-page adventures is being able to carry a narrative throughline across them in the limited text space I have to work with, without just cramming tiny font text on the page.