Listening to a two-hour lecture certainly has its merits, but you would also benefit from studying individual sounds in detail.
Phonetics: The Sounds of English and Spanish - The University of Iowa
I didn't study from this site, but this is pretty much how I learned to pronounce English sounds: written instructions on how to pronounce each particular sound accompanied with the corresponding mouth anatomy and audios of native English speakers.
I learned the English pronounciation this way in Korea, and although I hadn't had any real-life interactions with native speakers of English there, my pronounciation was perceived quite native-like when I first came to Canada. I still fumble at times when I pronounce words like 'community', 'deodorant', and 'rural route', but overall I think I've now acquired a native North American accent because most native speakers can't tell I'm a non-native unless I tell them or unless I write, in which I make grammatical mistakes quite often.
What I've noticed over the years of interacting with other non-natives is that many of them are well aware of their area of weakness in pronouncing consonants but not vowels. In my humble opinion, mispronounced consonants are not so much of what renders speech incomprehensible as mispronounced vowels.
I remember having been instructed to stick one or two fingers vertically between lips to prounce certain vowels, I now forgot which one corresponds to which vowel, but thinking back, that was an interesting method.
- HKB