Not being that familar with Sublime, I can't say much about them, but I like what little I have heard, to add to what lalimacefolle said, to get that classic Reggae sound also depends on the rhythym, Rock is usally on the downbeat, reggae is on the upbeat, in 4/4 that would be, 1 and 2 and 3 and 4 and , count that out and play on the "and", a kind of upstroke chop with the pick, immediately muting, not letting the chord ring, Later Mon.

Boom, chick, boom, chick, boom, chick, boom, chick, chick