Wow, it's been a couple weeks since I posted a Wednesday post.
Anyways... culture. What the social customs are - holidays, traditions, superstitions, even symbols. Culture is a big part of every life. Like American culture revolves around TVs and consumer goods. Like the Chinese thought (think?) that dragons are good luck vs. Western Europe thinking they're evil. Like some people throw a pinch of salt over their shoulder when they've knocked the little salt shaker over.
8 Ways to Make Your Character's World More Realistic:
1. Be consistent. If you have a holiday/festival dedicated to dragons, and then turn around and say that your world thinks that dragons are top-notch evil, then you have a problem.
2. Don't stop to explain the entire history behind the superstition. Would you be bored if I went on about how people say "bless you" after they sneeze because it was thought that part of your soul flew out when you sneezed? Well, perhaps you wouldn't be. But do you know anyone who would?
3. Make it sound natural. If you write general/realistic fiction, then make it at least close to accurate.
4. Ask yourself if your character is a noncomformist. Does your character live by these society standards? Does your character think that perhaps dragons are really blessings, and the whole "evil" reputation is a misunderstanding? Does s/he think that throwing salt over their shoulder to ward off evil spirits is stupid?
5. Think past cliches. Maybe rain is a symbol of happiness, or instead of saying "bless you" they chant "Stay soul" or something (I admit that was a little weak). But don't stick with the overused cliches of past literature.
6. Remember that you don't have to cram in every little detail. It doesn't matter if your world's got a moon-spirit festival in December if your story takes place within the month of June.
7. Don't make it all flowery. This might be a matter of opinion, but not completely. What I mean is, not everything your world has to offer will be good and wonderful. Some parts have to be bad - evil omens, bad luck symbols, the celebration of war, etc.
8. If your story focuses around a cultural detail, describe it thoroughly. For example, my novel focuses around this cultural slight: my MC refuses to let her sister marry this rich man. The rich man's aunt (because my world is matriarchal) feels slighted because my MC's species in general is endangered, and refusing a marriage offer is insulting. Without knowing that this is insulting, would you assume that the aunt is overreacting when she sends my MC to jail?
So, my list of tips. The most important thing to squeezing culture into your world-building is to find a balance. Not too much detail, not little. I can't tell you how to do that.