I'm not an expert language learner by any means, but I can give you a few tips that have worked for me and may help you augment your learning process. As David mentioned, it's important to listen to real speech so you can tune your ears into the natural rhythm of the language. I've found a couple of reliable sources of audio and video online that I can use for listening practice. For video, I just put 小孩子动画片 (children's animation) into the search bar on youku, and I can generally find something with easy children's vocabulary, and the visual stimulus helps everything sink in more. For just plain audio, I try and listen to an hour of Radio Canada International's Mandarin station. I can only make out about 20% of what they're saying at any given time, but it helps me improve the speed of my word recognition while getting me used to the speed and rhythm of the language. This in itself doesn't constitute a course of study, but I think it goes a long way to augment something like the Popup Chinese course material.