Problem with coming up with names on the fly is that if that NPC ends up being recurring person you don't want them to be named something that doesn't fit the game at all. Then you are stuck with the name if you goofed during the game.
One way to not have a "name generator" is to have a list of names that you have generated/came up beforehand. When you need one, you pull one from that and then cross that name over. You can also have another list that you use to pull a nickname for the character to give some direction for their character.
Having a wealth of good names for a certain setting in your head is hard to have. One of the problems is that in reality same names are used really often, and this was more prevalent in olden times. Still you don't want to use the same names twice in an RPG to be more clear who is who. Also, i'm not that certain how many characters would actually have names or at least names that don't just portray their occupation. Shop keeper could just stay as a Alison the shop keeper instead of Alison Weston. Pedestrians tend to have pedestrian sounding names.
But... if you still want to create cool sounding names and not rely on lists/generators, one can use something that i call the "MMO character name tactic". This works with adding two words together and the end result is a cheesy but somewhat cool name. Examples: Frosteyes, Ironfist or Deathshadow. To get on the next level of epic proportions you translate the words to a fantasy language. One i have used is middle earths elven. Rough translations for the examples would be Heleg Hend, Ang Paur and Gurth Gwathren.
In many ways names tend to describe the person much more than how western people are named nowadays with the name being completely its own thing that doesn't directly portray the person. For example if you use Sindarin elf name generator, the name is composed of few things that are then mashed together. In Japanese culture they use the suffixes to represent social status between the two people talking.
PS: No, i don't know how to speak Middle earth elven, i used translator.