Just be consistent and keep up the good work They will push every button they can. The distraction technique is a good one as others have said - a firm NO, removal of any offending items and then a complete change of voice and "Look what Mummy's got over here" etc does eventually work - they hear the difference in your voice and usually tend to prefer the 'nice' voice and reaction rather than the 'angry' one.

I personally don't agree with lots of cornered off areas/baby gates and removal of EVERYTHING - just breakables and dangerous stuff. I don't think it teaches them anything if everything is locked or blocked away from them - my SIL & BIL do this with their 3 year old DS and 1 year old twin DD's and have done since DS was born - and although it's fine and dandy when they're at home, whenever they go to anyone elses home or out in public they go on a rampage, pulling EVERYTHING out of everywhere and touching everything in sight they're not supposed to - my house always looks nuclear when they've left and that's WITH the parents running around after them trying to stop them. I think it's easier to teach them not to touch and respect what they can see. But that's just my opinion...each to their own