User reputation calculation is a fairly complicated process that depends on a variety of factors. The core of this process is hardcoded in our backend and is a part of the internal TradingView processes. Therefore, we are unable to reveal the formula. However, we can tell you the following factors, that can affect your reputation:
number of likes and the reputation of those who like your idea;
comments;
number of followers.
Please note that these factors are important, but aren't definitive. You can learn more about gaining reputation points in our blog post.