One of the hardest things I have had to do in this hobby is threading various, unconnected thoughts together. This is especially true in my newest world, as I began with five characters that had nothing in common. How does a fledgling worldbuilder bring these things into one solid strand of writing?
By Looking at other Things
When I start out with five characters, or two cities, or eighteen different types of dragon
, I find that by looking at a different aspect of the world, I can see how these disseperate pieces can fit together. Perhaps two of my five characters drink the same type of beer, one abstains completely, and the other two are more into spirits. Perhaps my two cities have symbiotic industries. Maybe those eighteen different dragons have a single area of my world none of them have ever been to. For each of these, I can ask why and how.
The two beer drinkers are actually fire forged friends, and rally around the same drink that got them through many a dark night. The spirit drinkers aren't friends, but they are connisouers and so run into each quite often, and competitive natures lead them to lose more money between themselves than on drink. The teetotaler may simply be the love interest of one group and the sibling of the other, but more likely is an avid opponent of the other fours debauchery and so comes to blows with them regularly.
Take a close look at small details that could be used to the a majority of things together. Characters can be tied to an Organization not by alliance or combatative status, but because that is just the best place to get a good cybernetic arm upgrade done. Tha k god for the free coffee too. A building may have once featured in a myth but is now just a place where lowlifes hang out. Figure out your worlds threads not by ramrodding two things together because they need to be, but rather by allowing the various parts to mesh like a fine tuned set of gears.