Do you want your world to seem more real? Maybe you should try making the people be like real people. How? Make them unpredictable.
Where Are They?
This is an easier one when it comes to characters returning to see people several times. Every once in a while, make it so the NPC they’re looking for is somewhere other than usual. If it’s the bartender, have someone sitting in for him or her while at home, sick in bed. Or maybe they’re running an errand. It’s quite simple.
If the characters are meeting someone for the first time, maybe make the NPC not be where others told them he or she would be. Again, errands could be being run. Or maybe the person just went for a walk. Or is in a meeting. Or was kidnapped not 10 minutes ago.
How Do They React?
Sometimes, a person will suddenly get very angry and you don’t know why. Or they’ll break down crying. Having a person react in an unexpected way can enhance your world
But don’t just make the NPCs act completely unpredictable. There should be SOME reason why they do what they do, whether you lets the characters in on it or not.
And remember, love makes people do strange things.
What Are They Doing?
Have the PCs catch the NPC doing something strange (at least to their eyes; context – and being able to see what is happening clearly – is important). Maybe the person is sneaking around, trying to avoid being seen. Maybe they’re talking with someone that you wouldn’t expect.
The things you do don’t have to be so blatant either. A person that the characters had plans to meet up with can show up late, talking about how the wife was nagging him, or how he couldn’t get the town gossip to shut up long enough for him to walk away. Little things are, after all, what this series of posts is about.
You can take almost all of these tidbits of advice and use them to create small hooks, too. What if there’s some sinister reason the bartender is sick, for example? Is the disease about to infest the town? The world? Is it a targeted thing?
Then, not only does this advice make the world more real, it also draws the characters to action. But if you only sprinkle in sinister things, you’ll keep your players guessing as to what might be important and what might not be.