I believe the same as you.. once you know and understand the world and places in which your characters will exist, it makes it so much easier to add depth and interesting details to the story. At least for me it does.
Below is part of a post I saved by one of the veteran guild members, Ascension. He was helping a young map maker with layout. It's been invaluable to me, perhaps it will help you as well.I am looking to learn and understand more about map making and geography in general to better help me in making I guess, accurate(?), or effective maps in the fictional world I have been developing for five years now.
Welcome to the Cartographers' Guild!
Well, first you have to get the mountains and hills in. Since rivers flow downhill it's generally a good idea to get those higher things in at this point. Sure you could put rivers in first and then decide where the mountains are going to be but that usually ends up looking slapdash and the arrangement of mountain chains is almost impossible at that point. So we do it like mother nature does it, put the mountains in then decide how the water will flow. If you feel like you have too much open space then put a few lakes in before the mountains. Remember that mountains come in chains, not circles or squares or mish mash here and there little clumps. Hills can be a lot more freeform. You might want to read through the tutorial section on rivers and mountains and whatever else is there to get some better understanding of natural geography and the processes that shape the terrain.
Once the mountains are in, put a bunch of foothills around them and then fill up some space here and there with more hills. Then you do up the rivers.
Think of a river as a tree growing from the sea going inland - put the trunk on the coast and the branches in the mountains. Make your river curvy and bendy, not straight. Sometimes there are deltas in lowlands so those can be like the roots of the tree; just don't make too many deltas unless you have a lot of swamps. Connect the lakes to the river system. Lakes have many creeks that flow into them but only 1 flowing out - it's a physics thing. Depending on how far zoomed out you are (like you're hovering up in space looking down) you don't have to put in every single creek, just the rivers that are big enough to see (ie big wide suckers) or are important for a story. I always put in a rough sketch of where I want some rivers but hold off until the very end to put in the final rivers.
Next decide where you want the forests. Forests can be put anywhere but if you want to get technical about it then you need to take into account things like latitude, temperature, climate, rainfall, jet stream, seasonal winds, rain shadow, etc. That's a lot of stuff to think about so if you don't want to then you don't really have to...but it helps for realism. Generally, I put forests around mountains, lakes, and rivers and always on the west side of mountains. Then I'll stick some in at the end to fill up space.
Plains go on the east side of mountains (this is the rain shadow) and in temperate zones. This area can take up a great deal of space if you want it to. Savannas are hotter and a bit drier versions of plains and I put these between plains and deserts.
Deserts are drier savanas so put those where it is hot and dry - not way up north and not right next to a swamp. On earth the deserts are generally located on the Tropics of Cancer and Capricorn but there are some others not on those latitudes.
Next you'll need some swamps (marshes, fens, bogs, moors, etc.) and those go where ever it is wet...cold and wet is a fen while hot and wet is a swamp. I put these around lakes and deltas.
Jungles are just hot and wet forests with different trees than in temperate or cold climates.
Once you have the basic terrains in (mountains, hills, forests, plains, deserts, swamps, jungles) then you can get exotic if you want and put things in like mesas, plateaus, cliffs, canyons, volcanoes, craters, etc. You can also get more specific terrain types like loess, tundra, tableland, scrubland, rainforest, etc. but you don't really need those.
With the terrain done now you think about towns. Cultures around the world (it's a human thing) always build settlements around where rivers join other rivers or where they join the sea or a lake so put your big cities in those places. Connect the big cities with roads and where the roads intersect that will become an important trade center so put some towns there. Villages are usually put where people need access to certain raw materials like iron or marble. Connect the villages and towns to the road system.
Next you have to think up names for all of those towns and cities and mountain ranges and creepy forests and foreboding deserts and pirate-filled gulfs. This is usually the longest part. Pick a font that fits the genre of your setting - don't use a Star Wars font on a fantasy map. The font should also be legible and clear; save the fancy fonts for the big title.
Lastly, put a scale bar on there so you know how far it is from one place to another. Put a compass on so everyone knows where north is - seems that it should go without saying but sometimes maps are made to fit the paper and therefore landmasses get rotated a bit. Put a fancy border on if you want and a pretty title. You can add some decorative illustrations around the edges if you so desire. If you really want to get technical put on some latitude and longitude lines and rhumb lines.