I think the major ingredient for HN is focus on topics that are interesting to "techinical" people. When you focus on particular set of activities it becomes easier to just say no to a lot of other contents.

I don't have twitter but i check some users(like the pico8 dev) once a week for interesting content. I don't see anything offtopic there and it's very nice and sometimes i learn something even in the replies. Same with certain subreddits. Just consuming in polling mode, helps a lot.