the worst totems they drop are Tremor totems and Grounding totems. (which respectfully dispells fear and eats the next spell cast on them)
easiest way is to let your pet attack those totems and/or wand them down (Whichever's fastest).
after that we have earth shock, which is a spell which interupts your casting and indeed silences you for that school for a few seconds Downside for them is that it has an 8 second CD. Most pvp'ing shaman have an addon which let's them see when you start to cast fear (enemy cast bar) I often trick them by starting to cast fear and then interupt and starting immolate instead.
a way to work around these two major defensive abilities is to get them mezzed (seduce/fear) asap (just watch out for tremor totem).
in my experience they all play differently, they can be tough. but most are utter noobs. but i learned to play against them by rolling a shaman myself
(know thy enemy ^^)