I have a blog for my company called mrchgrl merchandising + design. I know a lot of bands as well as merch people have a zillion questions when it comes to the do's and don'ts of merch and I couldn't find anything out there that gave any definitive answers for any of those questions. I'm lucky enough to have studied tour management and merchandising management in school and have been doing merch for quite some time, so I figured I'd give it a shot.
There is a section called "Merch 101" that I update weekly with new "lessons" about merchandising, it's mostly helpful for things like organization and professionalism, but it's a pretty handy tool and if anybody is looking for more information about any of that kinda stuff you can find it there!