What is the best way to build an entire world?

Hello, I am an amateur world builder and I am wondering the best ways to build a realistic world. I know I'm not the first to ask but I need a realistic idea of how long it may take and what the best methods are. I am currently working on a fantasy world but would like to know how to best build sci-fi worlds as well in the future.<br><br>The world I'm working on currently is intended to be the campaign setting for a Dungeons and Dragons game that I will be running and would like to release as a setting later on. <br><br>I am currently working on the maps, climate, countries, religions, and pantheon. <br><br><br><br>What would be the best way to go about this? And do you have any advice for how I could make the world feel fleshed out and realistic?