Let's say you have a really excellent world, and you've figured out a ton of things about it. The next step in story terms is to translate that world into the story and make it come alive. I've talked before about being careful not to info-dump - about managing and dispensing information in various ways (including Hiding Information in Plain Sight). But a lot of what makes a world come alive is not the information you know about it, but the feel of the place.
What creates the feel of a world?
Well, that information you've created will be useful. It's not going to be enough on its own to create a really intense feel. Here are some things that are useful for creating a world feel:
1. Objects that imply activities
I've mentioned this before, but objects can be extremely useful for creating world feel. What you need to look for is an object that is idiosyncratic. It could be an object designed for an activity unique to your world. It may be an object common to our own lives, but should take a form uniquely suited to the world you're creating. Like this Roman "Swiss Army Knife," for example. These objects will imply the activities and social circumstances they are designed to fit into.
2. Symbols that imply attitudes/judgment
Symbols can be found in lots of places. Real world cultures are full of them. In Japan, the moon is associated with autumn, and therefore can symbolize it. Colors can be symbolic, as when we associate blue with boys and pink with girls (don't get me started on that, but it is a symbolic color system). In your world, any of these things can be symbolic, and if they symbolize unexpected things, the feel of your world will be enhanced. Better still if those symbols can mean one thing to one social group, and another to another. In Varin, the nobility see the manservant's tattoo as a symbol of skill and subservience; other servants see it as a sign of elite education, pride and adulthood; and Lowers see it as a sign of danger (as do nobles who might be in danger of encountering their bodyguard skills!).
3. Metaphors that imply value categories
I can't overestimate the importance of metaphors in creating a feel for your world. We don't think consciously about a lot of the metaphors we use, but using them evokes all kinds of imagery that we associate with what is important and basic in our world. "Life is a journey" evokes all kinds of things, including old fairy tales ("off to seek his fortune"), the voyages of early explorers, the frontier, etc. If "life is a game" then you can go into all kinds of games that life might be like - poker will give you one feel, chess another, power and assassination yet another. In fact, I highly encourage you to create games unique to your world circumstances; they can be enormously important in creating feel!
4. Voices that imply, well, everything
Pay attention to your character voices. Because they are constantly present, they do an enormous amount of work in creating the feel of your world. They can help delineate social groups and world categories all over the map, and by casting judgment (as I've mentioned before in Subjective Point of View: expressing judgment with adverbs and verbs), they create an enormous amount of "world feel" while at the same time working for you in the areas of plot and character.
It's something to think about.