Re: Alternating picking
Metronome for sure, or a looping double-bass drum pattern. Basically anything with a mechanical timing to it to practice along with. Paul Gilbert had an exercise in Guitar World/School/For the Practicing Musician some years ago where he picked notes on two adjacent strings up and down the neck.
----12------10-----8-----6----4----2
--------11------9-----7-----5----3---
or something like that. Not adjacent notes, but either one or two frets apart (either chromatic or the whole notes on adjacent strings).
He expanded on it in a later article as a string-skipping exercise, where you start off on the 1st and 3rd, 2nd and 4th, 3rd and 5th, 4th and 6th, then 1st and 4th, 2nd and 5th, 3rd and 6th, in both directions, then in reverse order and both directions.
However, I'd start with one string, doing chromatic ascension and descent, using all 4 fingers.
Steve Vai's 10 Hour Workout is also good for this, where you go 1234123412341234 across all strings, then in reverse, from the 1st fret to the last, then alternate 12344321 on adjacent strings.
Be mindful not to lock your picking wrist, as that can cause trouble later on. You want to flow like water, naturally, not tensed up.
Early Metallica and other Big 4 Thrash is good for it as well, with the machine-gun palm muted rhythms, though it's not as mechanical as a drum loop or metronome.