Writing help

How to avoid informed traits

You know those characters that are constantly referred to so smart or so capable or so sensitive (etc. etc.) by other characters or in the narration? And every time it comes up you find yourself shaking your head or rolling your eyes because the character in question either is as bland as boiled potatoes or constantly acts in ways that contradict those claims without explanation?

That's what is commonly called an "informed trait". You're told the character is a certain way (or has a certain ability), but there is more or less nothing in the text to back that up.
It goes the other way around, too, with informed flaws that are supposed to make a character more relatable or interesting - think almost every romantic comedy leading lady who is supposedly "shy" and "clumsy", but in a cute, endearing way that only ever comes up when the plot asks for it.
It's frustrating, distracting, incredibly dull and at times downright insulting to the reader to encounter a story where one or more characters have a bad case of this, but unfortunately, it's a pretty common weakness even in otherwise strong, well-written stories with interesting and complex character concepts.

Since characters and how the reader feels about them (whether they are supposed to relate to them, look up to them or feel repulsed by them) can really make or break a story, informed traits are an easy trap to fall into and many a writer's Achilles heel.

So, how to avoid them?
This is where the trusty old "Show, don't tell" comes in. You have most likely been told before that it's usually better to go for subtlety and leave something to the reader's imagination than to spell it out, and that is true.
It's challenging to imply something without outright saying it. You have to get creative with the details you want to put into your story to get a point across by relying on your audience's ability to read between the lines, and while it's absolutely worth it to go the extra mile, you also run the risk of making your narrative too stilted and contrived instead.

However, there is a fairly simple trick to make your characterization feel more natural and insert it into the story smoothly:

Stop thinking of your characters as possessing certain traits and start thinking of their personalities as a collection of habits, preferences and specific abilities.

It might not sound like that big of a difference, but it will make translating your character traits into text much, much easier and save you a lot of trouble while editing.
Some examples:

A "smart" character
This can mean a lot of things. You could have a character who is booksmart, learns quickly, reads a lot, can retain information easily and access it when needed, but has trouble applying theoretical knowledge in real life, someone who entertains their friends by telling them about weird facts and trivia, someone who can still recite poems they had to learn by heart when they were ten, someone with a tendency to talk in such complex run-on sentences they frequently forget what they were talking about half-way through.

A "brave" character
Try to instead make a character who can never resist a challenge, who is a thrill-seeker and went bungee jumping about a dozen times already, who enjoys dragging their friends on the most dangerous looking rides in an amusement park and endlessly teases them about how pale they went afterwards. Make someone who simply cannot stand by when they see someone else get bullied, someone with a collection of scars they wear proudly and a story to tell about each one.

A "shy" character
Forget about characters who blush prettily when spoken to and that's it. Instead, write about a character who can't make eye contact without forcing themselves to, who stumbles over their own words when talking to strangers, who is afraid of wearing bright colours because it might draw attention to them, someone who is humble and polite, but distant and comes across as cold or uncaring because they have tendency to hide their insecurity by retreating into themselves, even though seeming rude is the last thing on their mind.

Insert these habits into the story wherever they fit best. Be consistent in the portrayal of your character's behaviour, even as character development kicks in. Adjust deliberately, but reasonably. After all, old habits die hard, so having your character break with one, however minor, can be a powerful moment with just as much emotional resonance as a flashy, dramatic scene meant to convey the same sentiment, and any "big" scenes will likely feel more organic if the reader has already seen traces of the necessary character changes before.