I don't think you have to do a whole lot different than daily, but somethings I keep in mind:
--I try to find the SP's who will get one or -- if possible -- two favorable starts (ie PETCO, not Coors, facing bad teams, etc etc) in my lineup.
-- I try to mix in a group of steady performers with guys who are on a hot streak and just hope it continues until I can change my lineups next week, so if they do go cold, I've got a chance to win the week if it's H2H.
-- Consider load up on RP's since they can usually get better numbers, though one bad inning can kill you, so beware on that one.
-- Watch the ww as much if not more than daily leagues. Since it's weekly, most managers won't be paying as much attention as your daily leagues, so you may be able to grab some guys off the wire that wouldn't be there in other leagues.
I should have probably prefaced this by saying I only played in one last year and finished 7 out of 11, so I guess you should take that for what it's worth.