Gossip

I had it from one, who had it from one....

I was once in a production of School for Scandal, Sheridan's irrepressible social satire, where a coven of wits and rakes assemble in various different salons for the sole purpose of character assassination; the result a kind of venomous meringue -- sugary lightness laced with poison. It's irresistible because the bitching is always elegantly done and everyone is fair game -- each of the characters gives as good as they get.

I'm mentioning it because this particular Restoration comedy is a fantastic example of how you can use other people's points of view and opinions to throw light on character. Even the spikiest observation can be informative, both about the speaker (why are they being so malicious?) and about the subject themselves.  It is possible to blend unreliable comment with something percipient and to the point, so that the reader has to exercise their own judgement and sift through what can be relied upon and what should be discarded, and in that way they become active participants in the story.

If you're looking for a little weekend exercise, give yourself license to have a really good gossip. Invite the characters in your story to a social function and let the backbiting begin.  It will provide you with the opportunities are some wicked humour, but also give scope for some poignancy and a few darker notes: sniping about people behind their back is a dangerous occupation, with consequences and the risk of casualties.