What is the most important attribute of world building? The same principle applies as regular novel planning. Believability.
Your fictional world can vary from the real world with magical elements (magical realism) to a completely foreign realm (fantasy). The sky's the limit as long as you are consistent. Your world needs structure, rules, and—for a completely fabricated world—even a map. Ever wonder why fantasy books include maps? A map is the very essence of a plan. You follow a map (or directions) to go from Point A to Point B. Different types of maps highlight different information—borders; location of cities; physical features—optionally including changes in elevation and landscape; climate; resources; and roads. Maps also need a scale and legend.
My world is Earth-based so I didn't need to create an original map. Google Maps provided all the information I needed for my research.
Once you determine your world type, you need to develop characters, varying from humanoid to alien. It's important to define physical characteristics, accents, traditions, familial relationships, and politics.
My characters are human with magical abilities, and I tracked their connections using family trees.
This is scan of my main family tree. I couldn't find a template with enough generations so I improvised. Kurtis and Alina in A Wizard's Choice tied all the characters from the series together. Even though they didn't end up romantically connected, this version of the family tree made the most sense. I use a few other family trees to record dates of birth and other information, including all the information on one diagram was too cluttered.
Your story has a setting and characters, but what happens in the beginning, middle, and end? Understanding plot structure is essential to keeping your story on track. As a reformed pantster, I see the value in using a plot template. I use a combination of the Three Act Structure and Save the Cat.
The Three Act Structure is the perfect example of plot, keeping to a basic model of beginning, middle, and end. Act 1 sets up the story, presenting the setting, characters, and conflict or reason for the story. Act 2 provides clarity on the conflict and questions the protagonist's chance of success. Act 3 brings the conflict to a conclusion and ties up any loose ends.