I personally subscribe to the notion that the best defense is a good offense.
When you come under attack, the best thing to do is to counter attack. Round up your catas and cropkill the attacker. You will need a strong offensive army to do this. You may still lose some troops in the process, but an attack completely neutralizes the threat – and the attacker will stop attacking you after this.
If you’re not convinced that attacking is the best defense policy, then let me explain with a little true story.
When I had recently taken over an account from another player, it was constantly under attack. This player would attack a few of my villages, raiding it and also cata’ing some structures in the process. I ignored his first attack, but as soon as his army returned, he sent it out to attack me again.
I checked with the previous owner and found out that this guy has been attacking for weeks now, and he had just put up with it.
As for me, I was angered by the attacks. Both of us had about the same number of villages, slightly over 20. To show him that I cannot be attacked, I sent off 3 cata waves and attacked 20 of his villages (out of 25), sparing only the small villages below 400 in population. Nineteen of my attacks were fakes, and one was real and that real attack smashed up his village well. I avoided sending real attacks to his capital.
On seeing this, he launched another round of attacks at me again. And as soon as my troops returned, I sent off again another 3 cata waves to almost all of his over 20 villages. As with before, nineteen were fakes, only one was real.
After smashing his second village, guess what? He never did attack me again. He stopped all attacks and never bothered me again.
When you show your aggressiveness by attacking the attacker, you send a clear message that you are somebody who cannot be attacked. But when you attack, do not attack just one village. Attack ALL of his villages with multiple cata waves in each. And hit him hard in the real attack. That is your best defensive policy.
Having a strong offensive army is the greatest defense against players in your neighborhood. If you lack a strong offensive army to cropkill your attacker, then get in touch with your alliance members and plan an organized attack. This is much more effective than defending and asking for reinforcements.
However, a strong offensive army will not prevent attacks against you during an alliance war. In contrast, if you are a big player, you tend to become a target of attacks because your enemy alliance fears you and deems you to be a threat.
In an alliance war, you cannot hope to defend against a coordinated group of players. You need to depend on alliance reinforcements.