Check out this sweep-picking exercise I've been playing around with today.
I like how this moves through the Am-F-G-D progression using the same arpeggio shape and shifts it around the neck to the appropriate keys.
This is also a great pinkie finger exercise, as your lil' digit will be working overtime to complete this sequenced melodic phrase. 
Check this idea out and let me know what happens.
Thanks!
\|m/ ROCK ON \m/