1. Especially with DnD, it’s easy to fall into the trap of asking the players for a lot of rolls. Rolls are slow and disrupt the story telling. Only ask for a roll when the outcome of the roll changes the story, otherwise just narrate what happens.
2. Take a look at what sort of skills the players have chosen on their characters and what they bring up in their background story. They usually hint at what they want the story to contain.
3. Whenever I create an NPC, I usually write down a couple things that make them in some way memorable. An easy way of doing that is by thinking of at least two other people they relate to, or coming up with things that are going on in their own life. E.g. the blacksmith is friends with the hunter, the inn-keeper avoids the midwife since she gave him a bad remedy, the stonemason is the brother of the baker and very excited about his new nephew. I once DMed a Shadowrun game where the players crashed with a plane in the Caribbean and made it to a little island, an they ended up walking around talking to everyone in the town on the island for ~3h, because I had drawn a little graph of X knows Y, Y is the aunt of Z, etc. That did abruptly end, when a little old lady summoned some insect spirits, though… 😈

Generally, my preferred way of organizing the game is to drop the players into some sort of world where something is already going on, and there are at least two NPCs or factions pursuing an agenda that would eventually lead to some shift in the social landscape, but the players happen to stumble on some whiff of that and are either going to be affected by it, or in some other way invested, and in a good position to do something about it.