I use tools such as Google Maps and Open Street Maps, and I cut/paste, mostly just by eyeball, with the relevant things I might be interested in - the train stations of Rome, for example, and so on. Google Earth is also great for this, but I confess that the last one I made for myself (Berlin), I just screengrabbed and pasted my friends # in place, with the train details, etc.

There's something comforting about knowing how to get around when the power goes out. Since I enjoy roaming adventures requiring navigation, making little maps for myself is basically just how I roll .. got me where I needed to be.