Okay, so I stopped numbering them already. Moving on, this tip is for those writers of Fantasy and SF in need of designing their own world. Where to start? You have some ideas but which way to go?
A step at a time, and the first step is simple. Break out some graph paper, 10 to an inch, and start drawing. Doesn’t have to be anything specific at first, just whatever coastlines and what-not that come to mind. If you have some kinds of terrain and places you would specifically like to include then make a list to have with you as you draw, ready to insert as your map starts to take shape. Don’t let the figures of physical limitations hold you back in your designs, just draw whatever you want. Later you can tweak it, apply some physical reality to it.

So the map is now drawn, complete with rivers, lakes, mountains, whatever. But dont merely draw the places where you think the plot will take place, draw more than you need, the entire planet if you need, at least in some detail. Better to have too much into than not enough. For instance, if some character might come from a far away land then you can have the name of said land and some general info about it; just enough to add some local color.

Now start up a notebook. This will be your Worldbook. In it you will record any information about your world that you may come up with. Anything from weather patterns and the colors of the moons, to cultural notes, different societies, what sort of unusual artwork the local elves like, anything that comes to mind. As your notebook grows larger then you can organize everything into the categories that you require. Just don’t over-think things at first. An idea for some detail of your world comes to mind, then write it down, even if it doesn’t fit anything yet, because it might fall into place later on.

When will you have enough detail to start writing? When you have enough to hang the beginning of a plot onto. I still find myself adding in some world background as my story develops, and all of it goes into my notes so I can keep things consistent later on. If the plot you have in mind demand any specific races, cities, or whatnot, then those should be written up in that notebook first. You will also find that some of those parts of the world that you just randomly drew in will later inspire some new plot point that you hadn’t originally figured on.

Building your world will be an organic evolving process that may not be entirely finished until your books are. Just remember to not let any preconceived notions get in your way. This is not Earth you’re making, it’s a completely alien world. Everything from the color of the sky to the types of clothes people wear is up for grabs. Don’t compare anything to what you know of Earth and Earth history. Just because the Dark Ages on earth didn’t have asphalt roads is no reason why your world at some equivalent age might not have them, just make sure there is a reason. As long as everything about your world is internally consistent, obeys its own logic and rules, then it’s all good.

And don’t forget to let the imagination fly!