It really depends on your stay (or whether you're a local). If you're only able to do one night, rushing through all the houses with express is probably the way to do it - the houses are the main attraction, after all, and you only have a few hours to cram everything in.
But if it's at all possible, I'd recommend slowing down. There's lots to see and do. The scarezones are good fun, for example! There are props to look at and little mini-shows to see, from dance numbers to murderous skits to the occasional insult comedy bit. There are characters that have their own little ticks and quirks and you actually can interact with them, unlike the houses where characters exist basically just to distract or jump out. Some people love taking pictures of the twisted iconography or selfies with the monsters, other people like grabbing a drink and watching people get scared, and still others just like to absorb the mood (which can vary from a campy spooky party like Killer Klowns or Vamp '85 up through genuinely unsettling and aggressive like the chainsaw clown horde in the Simpsons).
I'd also recommend doing the houses more than once. While nothing beats a really great first run-through where surprises await around every turn, going through a house more than once is often pretty rewarding. There may be scares you missed the first time around for any number of reasons - the timing was off, the scare actor wasn't working that shift for some reason, you got caught up in a cast change, or maybe in the din of it all you just completely missed it. Or heck, maybe you forgot about one or two that *did* get you the first time. Either way, going through houses multiple times tends to reveal a lot of stuff you missed the first time, and while nothing is as sweet as that first walk through there's still plenty of enjoyment to be had soaking up the artistry, construction, and environmental storytelling if nothing else.
Then there are the shows. While I do miss the past few years where we had two different shows to go watch, AoV still puts on a pretty great dance show. It's not exactly terrifying, but it's loud and bombastic and high-energy, and the scenes they show tend to be tinged with aggressive/monstrous implications if not literally trying to scare you. It fits in with what HHN has sort of turned into - a spooky, horror themed party. Mostly it's a good way to get off your feet for a bit while still having a good time, especially if you've been hitting the houses hard.
Depending on your disposition, there's also merch. This varies wildly with how much disposable income you have and how much you care about the properties on offer in any given year, but it's at least worth stopping in the tribute store to see what they've got. Like, it's crassly consumeristic and I don't know how much anyone *needs* a Killer Klowns from Outer Space lanyard or a Hellbilly Deluxe t-shirt, but still, if you're looking for ways to make the event feel more meaningful that kind of stuff might help to get you in the mood.
Food remains like, the one big thing that kind of sucks at HHN (and in the parks at Universal more broadly). Still, it's not like there *aren't* traditions here that make HHN a bigger event than "slam some houses and hit the bricks." Twisted Taters are beloved, as are Pizza Fries. There are specialty drinks unique to each year (RIP Jack'd Up), and lately they've started doing themed foodstuffs for properties (all the Stranger Things waffles stuff, surely to be expanded with some Scoops Ahoy ice cream options this year). So that, too, can elevate the evening from "let's do four houses and grab something at Finnigan's" to a bit more of a special/event thing.
It really depends on what you're looking for and how much time you have. If you only have one night, and/or you just want to get most scared you can be as fast as you can, hitting up the houses and bouncing is probably the way to go. But really, HHN (and this is increasingly true in recent years) is less of an event aiming to scare the pants off of you and more of a big Halloween themed party celebrating horror films, spooky moods, and the occasional fright. And if you can approach it from that perspective it's a really fun event that has lots to do.