I guess I will give a somewhat serious opinion as well. I agree that the story must be good. To keep your readers engaged (in the meaning of reading every single chapter) the story must be good. It must be interesting, well written, and blah-blah. You can define the meaning of a good story by yourself.
But there are another few things you should master. First of all, cliffhangers. You are writing a web novel. The ending of each chapter must entice the readers, make them want to read your next chapter. If there are too many cliffhangers, it will suck. If they are written badly it will suck. Writing a good cliffhanger is a skill of its own.
Secondly, you should make a strict schedule. It doesn't matter what happens to you IRL most readers won't wait for you. You should adhere to a strict schedule. That way, readers will get used to reading your novel.
And lastly is the length of each chapter. You should find a perfect balance. What I mean here, the chapters PROBABLY should be longer than 1.5 thousand words, but PROBABLY, less than 4 thousand words. It is somewhat connected to the schedule because you should arguably release more than one chapter, two-three chapters are the ideal amount. Too much, and you will tire the readers, too little, and they will get impatient\bored.