The technique this exposed me to most recently was ghost notes. I could hear them, that little thud before a beat in funk songs, but I couldn't do them. I was trying to play them by muting the string with just one finger on my left hand. This kept producing harmonics-- the trick is to use two fingers on your left hand to mute the string. BAM-- ghost notes.
Only working on one song a week isn't enough though. I've found that I'm able to learn two or three simpler alt rock songs at the same time I'm working on a tougher song. And to be honest, playing simple roots and fifths is damn fun. I've got a nice little playlist of songs to play along to; I'm getting close to 30 minutes of material to work through almost every night.
This way I'm learning the tough stuff and building up my endurance at the same time.