This is a very broad topic - since a significant part of what judges do is judge events, I feel like a blog that's devoted to “how to judge events” would have to either skim the surface or put out a massive amount of content, much of which would get outdated quickly (“How to quickly count all the decklists at an event!”) or be the subject of considerable debate (“The best system to manage ODEs at a GP!”).
Fortunately, there's a great place to obtain a ton of logistics advice: the
Tournament Report forum. Here, you can read an arbitrarily large number of reports about logistics at real events of all sizes, and see the feedback that judges provided on how logistical problems were solved. If you've got questions, you can (and should!) ask them - the writers of reports put a lot of hard work into writing them, and they'd love to see that people are finding them useful. If that looks a little intimidating, QJ Wong and his team at Battlefield Forge regularly post some of the best reports
on their blog for you to review.