Avoid the posts with more than 100 comments.
Try to go to https://news.ycombinator.com/newest and find interesting small post. I like when they have like 10 comments, but sometimes they have no comments and you can have a nice conversation with the author or someone of the community of HN that is an expert in the subject. [Note: Most of the post in "newest" are not interesting. You must check it for a while until you find one.]