Exactly as the question suggests, how do people go about making their own maps? What software do you use and how easy/hard would you say it is to learn said software. I really would like to get involved in this type of thing, switching to digital maps, but I haven't been able to find a viable method yet. I would really like the maps to look as good as the real productions but for homemade campaigns. Thanks in advance!
I use MapTool to draw maps for my PbPs. MapTool is an early, free, open-source Java-based VTT. I don't use it as a VTT anymore (Roll20 is so much better), but it has some decent built-in top-down cartography tools. After making the map, I then use screen capture to cut what I want from the VTT screen, and then I plop it into a shared Google Doc Drawing file.
They don't look as good as professional maps, but they're decent, and I can churn one out in less than an hour.
I use Gimp, It has a bit of a learning curve but it's really just a free version of Photoshop.
If you're looking for Tutorials the Cartographers Guild has a lot of great resources. I would recommend checking there they have a many great tutorials for battle maps and for world maps
MapForge would be ideal for this. It didn't exist when you first asked, but now it's a good option whether you're making maps to print or for use in a virtual tabletop app.
I use Illwinter's Floorplan Generator to make the maps, for use with a projector mounted to my kitchen ceiling and it works great. Here is a photo of a map I made for Doomday Dawn projected onto the table. For maps with areas that shouldn't be seen all at once by the players, I open the maps in GIMP and use a fog of war layer (just a solid black layer covering the entire image) over the top and erase parts of this layer as the party explores.
I also like using pre-made dungeon tiles (Dungeons in Blue are excellent for that old-school vibe) and assemble them in GIMP, then use the method above to erase the fog of war layer.
However I create the maps, I use layers in GIMP for things like secret doors and such, having them as not visible in GIMP by default, then when the players find the door/area I mark them visible and they show up on the projected image. It's a really elegant solution, I think.