When I first started weightlifting, I took a short 4 week class (2 days a week). I got the basics down and most importantly I got hooked to weightlifting. My technique was always a little "rough" to say the least. I knew I could do more and be better with the right direction, so I set a goal to find a coach. I took a seminar with Don McCauley before I tried out for the Muscle Driver Team. During the seminar, everything made sense and I was moving really well (I even Power Cleaned 140kg which was a PR at that time). Don had introduced me to sweeping the bar, and it made a HUGE difference.
After the seminar I kept trying to train myself the way Don had taught me. It was terrible, I couldn't move right and the bar would never get into the same spot. I was not lifting like I was when Don was giving me the right cues. I was very frustrated. I realize now that the reason I couldn't lift right was that I was fighting against my well rehearsed bad technique. I should have reinforced what he taught me by looking at videos of lifters who he had coached or mentioned at the seminar. Once I actually started doing that, my technique started to make a "permanent" change for the better. Videos like these would have made it even better. In the end, when you are frustrated and mad because of weightlifting, watch these videos again and again. This will help your body and brain make the connection about what you're supposed to be doing when you lift. And most importantly, keep at it!