Touchstones. Usually when you hear this term, it's talking about an object, or smell, or something concrete, that you can look at and remember something good. Like a pin that reminds you of a vacation, or the smell of cinnamon and oranges that remind you of Christmas when you were seven. It's a term that comes, I think, from gold making, but I don't know why I think that, so don't quote me.
Let's quote wikipedia instead.
.A touchstone is a small tablet of dark stone such as fieldstone, slate, or lydite, used for assaying precious metal alloys. It has a finely grained surface on which softmetals leave a visible trace.
See, gold making. I was right!
Essentially, it's something common that shows gold in other things.
This term also applies to characters, and it a really useful tool in storytelling.
The Touchstone is one specific character who helps the audience decide who to trust. They are usually a minor character, someone who has a reach into upper class and lower class, who is likable. They are a character you sympathize for, but mostly they are just a character you trust, because they are smart, selfless, and the dog of the story that if you kick them you've gone too far. They are a common stone, but who they are reveals the character of more shiny characters.
The first one I ever heard of was...Touchstone from As You Like It. The world of that play is very gray and murky, and it's hard to tell the good guys from the bad guys. It's hard to tell who to trust. If you have a story like this one, consider adding a Touchstone character. Touchstone(the character) is funny, but he's not over the top goofy, or stodgy. He's smart, and quick-witted, but not so courtly that you see him at a distance. He is the voice of the audience, so when he chooses a side, that side becomes the good one.
Another example, is Anna from Downton Abby. Yes, I talk about Downton Abby a lot, and that's because Julian Fellows knows his stuff. Whatever you think of the show, you have to admit he knows how to tell a story. Whenever I learn something, I think I wonder if they do this in Downton Abby, and the answer is often, yup.
Anna is a ladies maid, so she has a reach into both classes of the story, but she's more of a regular person. Even her name, Anna May SMITH, sounds common. You probably know someone very similar to her.
Her liking Bates makes him likable. Her not getting along with O'Brian, puts O'Brian on the outside of people we trust (also her hair does that, but that's another blog post) But the most useful thing about this storytelling wise, is how Anna liking Lady Mary makes Lady Mary likable. This is really useful when you have a slightly less than perfect or likable Hero.
Heroes have to grow, so that means they have to start off, sometimes, as weaker jerk-faced losers, and grow into their trophy and happy ending. While they are in that beginning stage, it's so important to have someone like them, otherwise the reader might just get fed up with the character, and not care enough to see the growth. If you make that someone a common man, a smart, all seeing, likable, regular person, then the reader will put themselves in that character shoes and like the character too, see the good in that character the way the Touchstone does.
Hero: Hi! I'm a whiny insecure hero to be.
Touchstone: But look how kind you are.
Reader: Look how kind that whiny insecure hero to be is. I like them.
Touchstones can be a larger Character (like Anna) and be useful for a long period of time. The reader will grow to trust their opinion on all people. While this character can grow, you have to be careful with them, because they are the face of the reader, so if you, say, have that character be attacked, it will feel more personal to the reader. You can use this, but you must be aware of this cost. And also, if you show them as wrong, it will dilute their effectiveness throughout the story, so you have to be careful. Weaken the Touchstone, and you weaken their effectiveness and the likability they have given. If Anna is wrong about Bates, then somehow that diminishes your opinion of Lady Mary, even though it's uncorrelated.
When you've created a Touchstone, how the Hero relates to that Touchstone is essentially how the HERO relates to the READER. So you can have the Hero be rude to everyone else, but they must be kind to the reader...i.e. the Touchstone. They must always apologize to the Touchstone if they are not, and if the Hero does something extra kind to the Touchstone,( like give her a present, or let him sleep in a warmer spot) even if the Hero just killed a thousand people, or just did something awful, the reader won't hate them. USEFUL!
Touchstones can also be really minor, and only really have a few moments in the story where they make the Hero likable and then go about their common everyday lives. But they are so useful, you can have them come back as needed whenever the hero needs reminded of their humanity, and their potential for GOODNESS. (Not greatness. Goodness.) So if you have a unlikable hero, and you want to make them likable simply, you can insert a Touchstone and move on with a damaged, but likable hero.
Either way, they're interesting. Now that you know about them, you will see them everywhere.