Extra gross Beholder designed by DireNumbat, my current DM.
I have an unfortunate love of problem solving and tweaking, plus a high standard for the tools I work with, so when I was DMing a game of Dungeons & Dragons a few years back, I took it upon myself to create my own detailed battlemaps for combat. Drawing a map is one thing but I wanted a system by which I could do so quickly and which put most of the effort on the computer. Starting with grass and dirt, I moved through terrain features one at a time, building up my master battle map as I went and using it to create battle maps for encounters in my game as I did it.
Then, about a couple of years ago, I decided I should make them into a set of tutorials online for other people to use.
Er... And then I procrastinated for a bit.
Anyway...
The Premise
Photoshop has layer styles - special effects like shadows and glows which apply to a layer in your image. What is so useful about them is that they are calculated on the fly rather than applied just the once. So, if you apply a drop shadow style to a layer in Photoshop, everything you then draw on that layer will get the drop shadow.
A complicated combination of layer styles, however, and you can draw, with a single sweep of the mouse, a river.
Or paths, or rocks, broken ground, hills, sand, snow, ice... Once this is all set up, you can draw maps as quickly and easily as scribbling the basic shapes. This one, for example, is pretty slapdash. It took me two minutes and thirteen seconds.
I timed it.
What You Will Need
First and foremost, Photoshop. Much of this tutorial can probably be done in something like Pixelmator but I know that much of it cannot, too. Photoshop is your best bet.
Secondly, a passing familiarity with Photoshop. These tutorials would get far too bogged down if I went into every detail of how it is done. I will be assuming you are familiar with the software, although not necessarily an expert.
Thirdly, you will eventually need access to a colour, A3 printer to print the maps out so they can be used. Black and white is doable but not nearly as cool and A4 is just a little small to work with. Fortunately, A3 colour laser printers are far more common and far cheaper than they used to be.
Fourth, patience. There is quite a lot to cover but, once you're done, you can use this template to create battle maps in minutes rather than hours.