Are you the author? It's fine to post your stuff, but people get angry if you try to conceal it. Also, try to keep the post as dry and technical as possible, try to avoid "remarkable success", "impressive work", specially if it's your own.
1) Are you the author?
2) Just a fan of the project? A family member? A friend of the author? (I don't care about the details, so if you want to keep it secret it's fine for me. Just reply "2".)
3) You just found it and think it's good?
There are some initial recommendations in https://news.ycombinator.com/newswelcome.html and there are also the guidelines and FAQ linked at the bottom.
Also, there are additional recommendations written for YC companies, but the advice is good for everyone. Just avoid the specific parts, for example do NOT use "Launch HN".) https://news.ycombinator.com/yli.html
Just remember: avoid hype, avoid automatically generated text, avoid very short comments and avoid jokes.
Wellcome!