My main tip for worldbuilding is to not just think about how it affects kings, soldiers and wizards, but how it affects an average person. How is the life of your average shopkeeper or carpenter or artist different in your world from ours? What sort of things do they eat? If there's social media, what do they post about?
Too often people fall back on their experience of our world on the small details. What do the characters say when surprised? "Oh my god!" exclaims the character who lives in a polytheistic society! Why would they say "oh my god!" if they worship multiple gods? Stop and think for a second.
Think about things like:
What crops and animals are farmed and how is food preserved? Food is such an important part of a culture, and it can really ruin suspension of disbelief when you see like...people eating stuff that couldn't have been eaten in that sort of location/climate in a pre-industrial setting, or definitely not at their level of social status.
What is your society's stance on gender and sex? Is pre-marital sex okay? Polygamy? What's considered an acceptable age for marriage and sex and is that a law or just social pressure? How do people feel about same-sex relations and gender identity? Is there gender equality in your world? Is that purely on a legal level where women are legally permitted to do any job, but still face sexism, or is it a genuinely enlightened culture where nobody even thinks to comment on a lady warrior or a stay at home dad? Are people in your setting cool with trans and nonbinary people?
What sort of materials do people make their clothes from, how are they dyed and what's the fashion? Here in England, we used to actually have what were called "sumptuary laws" where only people of certain social classes could wear certain fabrics, and in ancient Rome, similarly only super-important people were allowed to wear tyrion purple clothing because the dye came from a rare sea creature. What are people's feelings about showing skin in public? How do people fasten their clothes shut (If I see zips in your pre-industrial Fantasy world, I may scream...)?
If your setting has the characters walking around with weapons, what's the etiquette and law there? Who is allowed to carry a weapon in a non-war scenario? How about carrying one unsheathed? What do you do with your weapon if you visit somebody's home? Are there laws about what sort of weapons different people can carry?
The little details are what really helps make a setting feel rich and real, so don't skimp on them!