My longest running campaign was Blades (once weekly for over a year). It's still my favourite system.
The core mechanics are really easy, GM sets the narrative scene and the player says how they respond then builds a dice pool and adjust for difficult actions or ineffective approach (position and effect - how good it will be if you succeed and how bad it will be if you fail).
The game is built to play on the fly with very minimal prep, the scenario in the book is a totally fine place to start and lead into my game. If you run through all the steps of the meta game (updating faction relations and you'll have a good idea which group now has beef with the players crew and as such likely happenings for your next session.
Get used to skipping the boring bits, blades works best when the PCs are doing crazy stuff and using the flashback mechanics to get into or out of trouble. Do any essential prep the crew wants to do for a job but then skip to the engagement roll and just get started, don't let them spend ages planning all the little details.
Don't be scared to throw really challenging scenarios at them (especially after they level up a bit), the PCs have loads of ways to get out of trouble and trauma is beneficial to them initially as it lets them gain more xp. Also death is always a narrative choice so don't worry about killing them by accident.
The setting is amazing, haunted steampunk Victorian Venice so you can lean into the spooky as much as you want. Remember it's always dark and life is pretty terrible for everyone who isn't super rich.
I'm happy to answer questions or bounce ideas with you.
Hope your game goes well.
No that's about right. My initial pre campaign prep was read the book and understand the factions, session zero to see what themes my players wanted to explore and what factions they were interested in interacting with.
Between sessions I only needed about 10 minutes to think about the next game, who was the job against, who's upset or happy with the crew currently, what factions plans are the players ignoring so are progressing unopposed and what does that look like. Was there any fallout from their last job. The way the city is set up every time your crew gets ahead it will please someone and upset someone else I found that made prepping super easy. Then all I needed was a list of random names for NPC's and I was happy making stuff up on the fly for the most part.
Some of them bigger things needed more thinking and prep like when they broke into the ghost hunters headquarters (I can't remember the name, guys follow the death crows and wear masks), that needed a little more time. Or when they accidentally summoned a demon I needed to work out what it wanted and how it worked. Side note demons are excellent fun and should be terrifying forces of nature in blades.