Gmail - how to protect the letter from falling into "spam"

More than once (including on Habré) it was noted that the Gmail spam filter sometimes mistakenly sends normal emails to "spam." Now this problem can be partially solved with the help of a new action available when creating a filter - “Never send to spam”. Thus, it is possible, for example, to set a filter that excludes emails from a specific sender or containing certain words, etc., from entering “spam”