hi guys…. so i have 3 decks stark sow/kill effects, baratheon hod the wall/domi, martell house dayne…. we play online at the moment on octgn so we have all cards and i just cant beat my friends lanni deck in joust….. could u gimmy some generall advice about plots etc which help and some specific advice about cards which i could use in the decks i run???

Without knowing much about his build its hard to give specific advice, but he's probably running a bunch of non-unique weenies?  The game is currently full of hate for those guys, things like Relentless Persecution, Pale Mare, etc; Targ burn would have a field day with him, cancelling triggered effects might be quite useful if he plays a lot of kneel mechanics (Martell has He Calls it Thinking, for example) and Ally hate like Varys, Oakheart, and Dissension will help clear his board out.  Rule by Decree can help keep his hand under control if hes abusing Lanni draw.

Cannot be Bribed, Cannot be Bought.  Put 3 copies of that in, it's a start.

If he runs a bunch of cheap guys (as seems to be standard for Lannister) then The First Snow of Winter should really crimp his style.  Forgotten Plans can take care of obnoxious intrigue plots as well if he is using them (Shadows and Spiders, Frey Hospitality).

Most importantly though don't use House Dayne.  Make a more traditionally competitive Martell build.  Sadly some of their good cards just got restricted but Martell KotHH is almost certainly still way ahead of House Dayne.