Hi, im new at this game, but I know how to do war. I have damaged all factorys and cities and I have only lowered the war index 15 points. What am i doing wrong?
Try damaging military bases, and if you have a land border, move ground units into the nation to occupy it (referred to as "painting" because the occupied territory will turn into orange blobs after a few minutes).
If that still isn't enough, start blowing up fortifications, attack their defenses first.