It's all here:
http://garywillis.com/pages/lessons/rhmovie/aagg.html
Like he says, practice this until you don't have to think about keeping your fingers on the strings. Concentrate on muting quickly with the following finger (keeping the notes as short as possible).
Then you can try this variation on the first excercise:
http://garywillis.com/pages/lessons/...ringcross.html
On his video, there's also an exemple where he starts on the B string and goes up from there. Good to practice string crossings.
After that, it's a matter of picking real music and applying. You can play the same E on the 2nd fret of the D string, 7th on A or 12th of E string. You choose where you play it according to tone, or what will come after so it's easier to play. Do the same with the plucking hand.
Say for exemple you have to pluck the E string twice and then the D string once:
1- pluck E string with 1
2- mute E with 2
3- pluck E with 2
4- mute E with 1
5- pluck D string with 3
6- mute D with 2
Think about muting before plucking. It is to get used to keep the fingers on the strings, ready to play. And the muting gives you a cleaner sound. Of course, in real music, you don't mute if the note needs to be sustained, but that's easy so you don't need to practice that. (experimenting and practicing with tone and vibrato on sustained notes is good but it's a whole other matter)
The ring fingers stays one or two strings above the others and when you go up, you lead with the ring, though sometimes 1 or 2 will lead if you go only one string up, or 2 will lead if uyou go two strings up. Depends on the situation.
It's really tedious work at first. It's not "hard" to do but your mind has to be there 100%. That's what practice is for. It's not supposed to be easy.
Search for Gary Willis on youtube.com and you'll find many exemple of application. Or search for "emilk" member of youtube, he posted all the Willis videos.
