What is the Blogging from A to Z challenge and where can I find more participants? Right here.

Beyond keeping your story straight and characters likable, you've got to know your own Jargon. If you're writing a story based in the real world, this would fall under doing your research and knowing what you're talking about. If you've made up your own world, well, you should probably also know what you're talking about.
Make sure you keep special words for technology, races, planets, gizmos and magical things straight. They need to be spelled the same, capitalized or not, italicized or not, used correctly by whomever is using them and possibly in a different manner by characters who don't. Write down the rules for the thing-which-you-have-created so that you, as the Creator of Worlds, make sure those things follow those rules and don't become McGuffins, plot holes, or any other point of weakness.
The things that you create should have purpose and meaning to the plot or character. Don't create or use spiffy words for the sake of tossing them around. If you're going to pull in some technical jargon the reader has to Google to follow the story, it better be worthwhile in the grand scope of things.
Have you spent days/weeks/months creating the most detailed galaxy and know everything about all seven plants and their collective fifteen moons, the nearby asteroid belt, and the two stars that keep it all habitable? That's great, but if your story only involves one of those worlds and has a legitimate reason to mention maybe two others but we never go there, we probably don't need the chapter of world building it would take to share all of that. Stick to what is necessary for the story. Adding a little more for flavor is fine, but don't drag down the pace.
I once created a bunch of spiffy items with rules and special words, only to realize I could get by with two of them for flavor and the rest weren't necessary to the story at all, fun as they were to create and awesome as they might be in my own mind. That epiphany led to a lot of hack and slash editing. As writers we love to create things, but we also must learn when to cut them. (Tune in tomorrow for more on that.)
Today's post breaks down to a simple: Know thy shit and use it wisely.
Have you created something nifty only to cut it later?