The only mod I ever used was a tile-set mod to replace all the characters with images, and I didn't stick with it. After a while your brain gets all blurry for a second and you start just being able to see your fortress instead of little ds and ks moving around.

Everything's going to be super confusing for a while, and you're going to have FUN (dying horribly in bizarre and interesting ways) before you get the swing of things. The community motto is "Losing is fun". For most players it's less about building a successful fortress than it is building a fortress that explodes, disintegrates, and sinks in to lava in a novel or amusing way that makes for a good story. So frustration tolerance and an "oow what does this button do?" attitude help a lot.