I'm mainly going for a 3-4 block high wall made mostly out of stone. I know there's plenty of room for improvement, any advice?
It depends somewhat on the context - what is around it, how long it will be, and so on. But I'd be inclined to get a different, contrasting texture in there, which probably would be wooden supports of some type.
It's very basic, but with the height restrictions you're going with, I think it looks good. There's not much you can do with short walls and there's enough texture variation for it to look good and not distract from the surroundings.
Maybe put stairs in between the fence posts so that there's a depression between the posts. Also, you could add a stony look under the posts too. Here is a picture where I reproduced your wall idea with the suggestions.