All good comments, including the getting the password joke (it was a joke, right?!)
The key is being on actively, so that you can see/dodge his attacks (and make sure your troops are safe, if you are away for 8 hours overnight, send troops on a 4 hour journey, leaving a few hundred scouts at home).
I would advise against nobling barbs in your area, if i were him and i saw you doing that i would go straight and noble your main village, which leaves you back worse than square one, as you will probably get farmed from that point on.
Get all your troops up, defense and attack, if he attacks you first, or you know which is his main attack village, i would suggest targetting that one first, esp if you can work out when he is offline. Troops over points, farm like crazy for resources. But the key is troops, and keeping them to retaliate with, until your farm is maxed out, you havent enough troops.
Nobling barbs wont get you anywhere. Life is for living, make an educated gamble, and dont be afraid to take risks. Too many players noble barbs and keep their noses clean end up getting nobled out anyway!