It's possible to honor someone by use of 드리다 rather than 주다 when they receive a favour, use of honorific nouns such as 말씀 instead of 말, and honorific particles like 께서 and 께.
I used to think that I should use these honor anyone that was senior to myself, but I then learned that I shouldn't, for example, refer to my mother honorifically if speaking in front of my grandmother (who outranks her).
Is that the only 'difficult rule' I need to remember or are there other considerations?