Great thread! There are dozens of good ideas here.
I'll add if you navigate on e-charts (like I do), check your back up devices for charge as well as navigation details (just as I did with paper in the olde days), before you enter.
Check your print guides.
Then hit google (most of our coasts will have reception).
We entered several
new to us harbors last season. My latest print guide for Southern NE was Duncan and Wares printed in,...maybe the 80's?

Some things never change so a print guide is always good to have.
Today, we have a world of info at our finger tips. AC is a source that I find very valuable. Still, outside of the 10% of the coast that 90% of boaters visit, there is surprisingly little up to date info on AC. But it's better than a print guide who's info was often a decade old when it went to print.
Detailed marine info is available googling various sources on the internet: travel media, blogs, Facebook, marine websites, forums(this one comes up), local papers, NYT's, etc. Be smart on your search.
Unfortunately, this new world of info comes with a risk: Like todays 'news', 90% of what you'll get is misinformation, so you have to be savvy about your sources.
An example was entering Biddeford Pool last season for the first time. The e-charts were up to date and accurate so navigation was easy.
But we couldn't get the detailed visitor info we needed. The general marine sources, print guidebooks, AC, either were un -detailed or out of date (things change rapidly).
Selective searching the internet when in signal range, blew these sources away for the details we needed.