In my younger days I took quite the number of top comments and since I've long gone into retirement I'll finally share the forbidden method.
All you need to get top comment is to be amongst the first who read the chapter. This differs from book to book and in some cases you'll need to be within 5 or 10 minutes of the release. If you've been actively following a few books, I'm sure you know the general time they'll release a new chapter.
Now the only thing stopping you from getting top comment is securing a slight lead. As long as the comment is decent, and as long it shows up at the top, even if it just has 3 likes at the moment, it will stay there. Of course you'll have to sacrifice you're mailbox as you'll be receiving hundreds of notifications if you consistently secure the top comment.
I've stepped out of the challenge more than a year ago and I still get likes on my older comments. Due to them I'm also able to estimate how fast and how much a person is reading a certain book. This is due to the fact that as long as they like one of my comments, it is inevitable that they will like more of them.
The simpler and shorter the comment, the less time you invest writing and the more likely someone will read it. Something as simple as "Looks like more people are going to die now 😄" works great. They also take no time to think up.
Eventually you'll reach the point where you've secured too many and realize it's all pointless. The only reason I secured so many wasn't because I memorized times, but because I was reading too much everyday. To the point that I'm not even sure If I slept more or read. Which now that I actually think about it, it isn't exactly that hard since I had a terrible sleeping schedule where 3 hours wasn't uncommon. Let's just say I read upwards of ~100 chapters minimum each day, however since then I've been able to completely stopped reading.
I will eventually try to finish all the series that I've started reading, but it's pretty much impossible considering how many books I have saved in Webnovel alone.