Keywords should be chosen very carefully. You can think of keywords as an exercise for an English class where you have to choose only the few very best (non-spoilery) keywords to describe the plot of movie.
Around 5-10 keywords for TV shows and 15-20 keywords maximum for movies is reasonable.
Indiscriminately copying keywords from IMDb is a bad idea.
Quotes, taglines, titles, actors, characters, crew, original story writers, networks, companies, award ceremonies and companies are generally not accepted as keywords.
We have a few exceptions, for example, some popular main characters that appear in more than one series, actors such as Marilyn Monroe who are the subject of many biopics or movie titles who just happens to be relevant keywords (e.g. Jungle). While award ceremony keywords should not be used movies nominated for e.g. an Academy Award, they can be used for documentaries on these award ceremonies.
There is no need to add the movie genres as keywords (e.g. "comedy" for comedy films, "drama" for drama films).
A notable exception is the "family" keyword. Family as a keyword does not have the same meaning as Family as a genre (i.e. the keyword can be used when family is a strong theme or when the movie is centered on a family). They can be used on the same entry (e.g. The Croods is a family film about a family).
Most trivia-based keywords (e.g. face slap, one word title) are better off as lists.
However, some trivia keywords such as "3d", "based on novel", "woman director", "duringcreditsstinger" are allowed.
Translated keywords are not yet supported. That mean no non-English keywords unless they are words commonly used in English.
Keywords should be objective. No opinion or judgment.
Keywords have to be added one by one (e.g. "superhero" then "los angeles" not "superhero, los Angeles").
Please use already existing keywords when possible (e.g. "miniseries" not "mini-series" or "tv mini-series"; "teenager" not "teenagers").
Years, decades (e.g. "1990s") and centuries (e.g. "19th century") keywords can be used when the story is set in the past or the future. For example, for movies released in 1975, a story set in 1960s is the past and a story set in 1980s is the future. The year/decade/century of the release should not be used as a keyword. Thus, keywords such as "future" are based on the year of the release, not 2017.
Non-relevant keywords will be deleted by mods.
Spoilers will be deleted by mods.
Contributors should not, under any circumstances, delete good keywords.
Pornographic keywords should only be added for entries set to adult:true.