Space is big. Really, really big. Not including a way for people to move between distant locations with relative ease can be a problem that quickly overwhelms a world. While faster-than-light travel or some form of equivalent (extreme engines, portals, cryochambers, etc) can cause issues with relativity and/or family trees, audiences have largely chosen to ignore that in favor of the benefits such an element provides. After all, mostly in science fiction worlds people want to see more than just the interior of a spaceship. Mostly.

While generating completely new kinds of creatures is unambiguously more creative, relying on age-old, tried-and-true inhabitants for your world is not necessarily a bad thing. These are elements that audiences are already intimately familiar with, and the number of stories and worlds that can be told with them are in no way exhausted. If you are creating a new kind of creature that fits with every Dwarven archetype but isn’t a Dwarf, it may be worth considering to just make/call that thing a Dwarf.

It’s the age-old conflict: good versus evil, and who will prevail? While many modern worldbuilders have opted to create morally grey worlds, this does not mean that your world needs to follow suit. There are reasons to create worlds in which everyone has some good or some evil in them, there are reasons to create worlds in which everyone is good and yet conflict arises from some outside influence, and there are reasons to create worlds where there is very clearly good and very clearly evil. Having your world contain a struggle between forces of good and forces of evil does not mean your world is simple, basic, or unimaginative (it may be, but it will be that way because of other reasons).

Maps are common elements in fictional worlds, but just because they can be overdone doesn’t mean they should be thrown in the trash. Maps can help situate an audience in an unfamiliar landscape. Perhaps more importantly, they can help provide a worldbuilder with a correct sense of scale.

Having humans in your fantasy world, or in your space opera that occurs across the galaxy, may not make sense. Afterall, in the grand scheme of things, humans aren’t all that special. Except, humans actually are pretty special. They are special because they are your audience. And it turns out that humans like learning about worlds that have humans in them. It gives them something to relate to. Audiences have learned to accept the fact that worlds long ago in far away galaxies just happen to have humans in them. They have learned to accept the fact that alien worlds with utterly different evolutionary pressures also generated humans (or a human-like species). They have learned to accept the fact that the strange new gods that created fantastic new creatures, also created humans. And audiences are fine with this.