Think of one thing you do in the course of a typical day.
I had coffee this morning and I don't know where it came from. I just went to the coffee shop and ordered it, expecting it to be there. I remember, a long time ago, that I decided that if I ever ended up in a strange world the first thing I would do is find coffee, get myself grounded over a cup of coffee. Then I wondered what would happen if I ended up in a world where ordering coffee was illegal (Kristine Kathryn Rusch does something similar in one of her Retrieval Artist novels). So, to continue the pursuit of coffee. I expected the coffee to be there. Why? Because that it my ordinary world. In my ordinary world I don't have to think too hard about getting a cup of coffee. Or a banana. Or a rare steak. Or sex. Okay, maybe I'd have to do a little work for that last bit, but that could be the beginning of a new world. What kind of world would it be where it is easier to get sex than it is coffee? Or as easy to get sex as it is to get coffee in my ordinary world?
One advantage of thinking of worldbuilding from the ordinary world of your characters? You get your reader oriented more easily to the novelties. You are starting in their ordinary world also.
Sarah stopped by the local discount market to pick up her two-buck chuck, deciding she wanted a skinny redhead this time. She was tired of the hunky blonds. They spent more time in front of the mirror than she did.
Running her thumb over her scanner she added the SKU to the barcode and headed for the transport tube. She didn't care that her more upscale neighbors saw her chuck half-naked. She knew for a fact that theirs were no better. Just dressed for the service. They all had the same equipment, did the same job. She could afford more but why waste the credits? It was a job. Kept people off the streets. Provided revenue for the state. Kept down violence and disease.
Sarah shrugged. Not bad for a couple of credits.
So, in less than 150 words we have met Sarah in her world. I have no idea what kind of world it is except for the details I've put here, but I'm now curious. Maybe not as a reader, but as a writer I am. It's an idea I didn't have half an hour ago.
So, here's a challenge. Think of something in your ordinary world, something that is so ordinary you don't have to think about it. Now, make it complex. This is the opposite of what I did. I took something that was for complex for me (getting sex) and made it as easy as buying a cup of coffee (easy peasy). How about getting out of bed? Or getting the mail? In what kind of world would those things be difficult? Can you, in a sentence or two, create an ordinary world that is far from ordinary?