Back when I wrote Character Foundry, I was assuming that most GMs’ minds worked as mine does - tons of ideas, and they just needed to be focused. Well, I’ve heard from some of the readers, and it is clear that not all GMs think this way. But I can still help.
I took off for a weekend last month
Just to try and recall the whole year.
All of the faces and all of the places,
No really - That’s the trick.
So you’re trying to come up with some ideas to fill out your town or city. You need some NPCs for the players to interact with, but you’re not really focused on anything particular. The next time you sit down to lunch in a public place (restaurant, cafeteria, whatever), look around at the other tables. Most are just “people” with their heads down and nothing for you to work with, but there will be a couple that show you a true glimpse of their lives. Maybe it’s that cute girl talking on the telephone and literally telling you (and everyone within earshot) all about her new boyfriend. She’s easy to turn into an NPC. Maybe it’s the mother with three young kids. Is she disciplining them or letting them run wild? Does she look like she has her act together or is her stroller leaking toys and other items? Bet you can just let your mind run for a minute or two and come up with a whole back story based on her.
OK, those are random NPCs, and you need something more specific. You need a mayor, or king, or ruler-type. Think back to your high school principal. Was he/she a tyrant? someone who desperately wanted to be cool and accepted by the students? a complete incompetent? Use that! Even if it is only your opinion of how the person was, use that. Make this NPC your high school principal.
Dislike using real people? OK, last film you saw - who was the bad guy’s henchman? Don’t use the main bad guy, because that is likely to be noticed by your players, but the minor characters - you can easily transport them into your game as NPCs. But remember to make them your own. Just because you are basing the NPC on some movie or TV character doesn’t mean that that is how they must stay. Maybe the character died in the movie, so you don’t know how they might have grown. That’s better, because now you need to role-play how they end up. All you’re really borrowing is some back story and some personality traits. You don’t need to use them as the next mission’s bad guy or bad guy’s henchman. They might make a great follower for your players. After all, how much work do you really put into NPC bad guys that are likely to die? But if he is a follower, then he’ll be around for a while and may need a back story and a personality.
The point is that you have a lifetime of experience to draw on. You’ve probably met a million people in your life. Few of them are memorable, but some are. Some can serve as the base for NPCs in your world.