Concrete Dungeon - Looking for tips running a city adventure

Ok. I really enjoy sandbox style games and big sprawling settings, but it comes with its headaches. Lord knows a non-proactive party can bring a game session to a crawl, and being overwhelmed always seems to be a problem. I've said his before, but it's all in the prep. And by that, putting guidelines to make the party work but not directing or leading the party.

At character gen, try to have it be collaborative and encourage the players to work with each other. Let them get to know each other's characters and support each other's characters. Put guidelines and limits, such as limiting psionics in this campaign so they don't discover the aboleth, or hermit characters powered by nature that may only want to leave the city. Make sure the characters have goals and are driven. Most of all, make them INVESTED IN THE SETTING. their family is there and may be put in danger. The item they are searching for is at the town in control lol of someone powerful. Out their power there that they have to maintain and nurture.

From there, make a few problems WITHOUT SOLUTIONS! If u don't have anything in mind to steer them too, U CANT RAILROAD THEM TO SOMETHING U WANT. It's scary, but it works. If ur players are good and reasonable, u can just go with anything they want. A prominent family wants them to break into an area and steal something. They want to go in gins blazing? Ok. They want to sneak in? Ok. They want to talk and lie? Ok. Sounds weird and overwhelming, but it's ok. It makes them feel in control and encourages the to make choices without rail roading them.

From there, your job isn't to fight them or let them walk over u. It's to reasonably complicate the matter. And any prep u do from here WILL HELP U if u remain flexible and patient. If they talk, maybe the guard they talk to has gambling and may later be caused to rat them out. If they fight, a few easy encounters in their plan, but something goes wrong to pin them down. They sneak, a guard patrol comes a bit early. Challenge them, but let them think their way out of it and go with it. Even if they fail, I've done the prep to give them a get out of jail free card in the story that will challenge them. They get caught, someone powerful gets them out and they owe that person a favor. They get dead, they remember dying but they wake up in a weird unexplainable circumstance. They lose the item, someone took it from them and now is a rival.

Complicate, but don't dictate. Let them go and take notes of the events. Who they owe, who owns them. Have a timeline in the background. If they ignore it, the plot moves forward anyways and it gets harder and harder to stop. It's ok to have an endgame, but it's how they get there that matters. And a lot of times, if the party is good enough, ull be inspired to add things to ur story and let them really effect it.

Plan a few pivotal things ahead, and put clues for them wherever possible. The part hears of people heaving voices and getting sick in the aboleth's psionic water. An npc they've been working for is slowly joking for position, so he frames party.