When your laying out the timeline of your setting there are a few core technologies that will touch most everything else, these are the things you need to decide first.
Most everything you do cost power, either when you use it or to make it. A great many things would become cheap if power were nearly free (like aluminum or desalination plants) or be all but unobtainable if electricity cost a lot more then it does today.
And of course mining or farming whatever it is that you use for power would be an important activity.
If your setting is going to change how we gain power (fusion for example) you need to put some research and thought into it.
This covers not only speed, but how people communicate and what it costs to do so. One way to get this set in your head is to think about how people who are poor, middle class, and rich talk to people who are nearby, a city way, and a world away.
Today communication is assumed to be instant, if we do go out and settle the planets then it won’t be anymore, light lag will be a real factor. Going to other stars would make light lag be even worse, easily a decade to get a reply.
And of course even if we make some sort of FTL engine that does not automatically mean we have a FTL comm system. Or that FTL comm’s are cheap.
For most of human history we could only send messages as fast as we could send a person, we may return to that someday.
Honestly I would say this is the most important, how easy it is to move people from one place to another is the most pivotal part of your society. It changes where buildings are, how big cities are and where people live.
If you can’t travel faster then you can walk you have to live near where you work. If you can teleport anywhere you want you could live on top of a mountain and then work at a fishery. If we could teleport we might not even have cities.
It also effects the gritty details of your story, how does your character get to his job? When his mom wants him to visit him across the city would it take him a day or an hour to there?
Cost of living technologies
By cost of living technologies I mean the technologies we use to get food, lodging, water, and medical care for everyone.
A society that requires half its resources just to provide the basics for its people would be very different from one that needed only 0.1% to do the same.