How do I get better at improvising city features?

A common situation is that the party is in a big city (maybe one you created yourself, maybe one from a published source) walking through the streets, just roaming around.

And then the question is asked: “What do I see?”

I always have trouble deciding what they see.

Most time I say a tavern, blacksmith or a clothes shop, but that feels very boring to me.

How can I get better at improvising shops and other facilities on the spot during city exploration, to increase the variety of description, and maybe open new possibilities for the party?