Long term war tactics that i have seen are as follows.

1. Every player in your alliance should train scouts... and every day you guys kill there scouts making them blind. Extra or left over scouts can be used to bomb which kills there troops and raises there honor.
2. After you break a city have a player who can not capture it spam it with attacks and get your enemy to reinforce it it easier to kill of troops with no wall defenses.
3. Try to work on 1 player at a time... Find all there cities and go after as many as you can at once try to overwhelm them.