I've been putting the spotlight on some more background ponies recently, and it's been getting me thinking. Background ponies are a lot like OCs, but there's just enough difference between them that you've got to pay attention. These ponies have a given setting. I'm always a bit irked when Vinyl Scratch shows up in Canterlot so she can be shipped with Octavia. Sorry, but we've seen that she lives & works in Ponyville! If you want to say that she moved to Ponyville later or moved to Canterlot from Ponyville then you can do that, sure, but at least say so. The show creators are really just drawing BG ponies more or less at random to fill scenes, but that doesn't mean you can't use their appearances for cues. Go to Winter Wrap Up. Find your BG pony. Which team was she on? What does that say about her? Things like that. That's how fanon develops anyhow. Bon Bon x Lyra and all that.
Speaking of, a very important thing when you're writing a BG pony is to actually write her. As in, do the writing yourself, and don't let fanon do all the work for you. I dislike the homogeneity around some of these characters. There's no reason a pony with an hourglass cutie mark has to be a dentist. Call that wall-eyed pony Bright Eyes, go ahead! Maybe she doesn't even have a daughter. These characters are excellent places to blur the lines between original and fan fiction, with far more leeway than we usually have. I don't want to see that lost to an ingrained fanon that makes readers reject or criticize pieces as if they had contradicted actual canon. For goodness's sake, that's one reason I wrote Kindness's Reward. I had a point to prove - Trixie is a character of her own right, not a prop, as she's often treated in Twixie ships.
Of course, while you have a lot of leeway, there's still cues to take. Look at Applejack. Can you imagine Rarity's voice coming out of her mouth? She's designed to suggest certain things - in Applejack's case she's exceptionally one-dimensional, and in fact her character design sums up... pretty much everything about her. For another example, let's take Cheerilee. Would "smiling sunflowers" suggest schoolteacher to you? Not necessarily, but it's not contradictory. Making her a nurse's assistant or such would've also worked, but you wouldn't have expected her to be a baker, would you? So Roseluck probably does run a flower shop, but then again, there is leeway to be had. Especially with certain cutie marks. Ditzy Doo's bubbles probably don't directly relate to bubbles (my own fanfic aside) but perhaps she just tends to drift where the winds take her, bringing smiles to those who look up as she passes.
The character doesn't exist in a vacuum either, and the best way to define one pony is to define several. If you say "X and Y are friends" you have to say why, and that defines them both. Perhaps they're both in the same business, perhaps their families are close, perhaps one's secretly crushing on the other and tried to get to know her when she saw her pass by one day. Works especially well for very different personalities, because you usually have to dig a little deeper. Maybe X is extremely hard working but would go crazy if Y didn't drag her out to have fun occasionally, and as much as X protests, she secretly knows she needs it.
Whatever you do, don't make an AJ either. You shouldn't literally draw their entire personality from their appearance. A flower cutie mark may suggest they run a flower shop or love growing things. Great. Now, what do they do in the winter? Are they a morning person or a night owl? What do they do in their off time, and who do they spend it with? What are their life goals? Have they dated much? Where were they born? You don't have to actually think out a series of questions like these, but the point is that if any one of these questions were asked you should have an answer. More importantly, your character should have a reaction to any situation they're in. A good test of how deep a character is is to see how they'd respond to an outrageous situation. What if a lifelong friend or total stranger walks up one day and kisses them on the lips? What do they do if they're shipwrecked on a stranded island? If it's somehow up to them to stop the princess from eating the dragon? A flat character only exists effectively within certain parameters. If you don't know how your character would react in an outrageous situation, think why. What personality trait are they missing? Maybe you haven't considered how panicky or calm they are, how logical or emotional, etcetera.
Also a special note: A unicorn has magic to aid with their special talent. This is different from their special talent being "being good at a certain type of magic". My interpretation of Colgate is that she essentially acts as fate's wildcard, her talent being that she can pinpoint the path a pony is on and where it leads, and she has magic to assist with this, most notably seeing a pony's "hourglass" of life. This doesn't mean her talent is that she has powerful time magic - not at all. She accomplishes her talent through mostly mundane means, with magic to help guide her. That kind of thing.
You know I had more to say but have forgotten it. Isn't that always the way? Anyway, may edit this later.
