1) Some traps I do not use (like giant bomb- because they are too expensive) but in the wars are necessary. I have a Giant bombs at the corners. but if you drop a trops (like 1 archer) in the corners bobms explode and you lose gold. I suggest that any traps have on / off button. and when you push re-arm all your traps, armed only those traps that are on.
2) when your village is under attacked - watch live (now you have to wait ... Your village is under attack)