The Golden Rule basically states that in most cases we should treat other people the way we would like to be treated ourselves. This is an important principle in most religions of the world and also in Humanism.
The Golden Rule is a general principle as experience shows that different people have different likes and dislikes. We should not force our tastes onto other people or treat them exactly as we would like to be treated.
Despite the above we should try to empathize with other people and to consider what they would want/would want to avoid. This can do a great deal to help us work out what will benefit other people and what will harm other people.
Moral principles generally vary enormously between groups, between different religions and between different sects of the same religion. Despite all this the Golden Rule is found in a great many different religions and different cultures because it has been shown to work.