Arbitration: Members promised not to go to war until they first submitted their dispute to arbitration
Collective Security: Members bound themselves to help any member that was a victim of aggression, preferably by economic sanctions rather than arms.
Assessment of the League:
Although a good idea, in reality it didn’t work. First, membership of the League never represented the whole community of Nations. Originally, Germany and the Soviet Union were not members, but more importantly, the US refused to sign the Treaty of Versailles, and thereby also refused membership in the League. Moreover, the League had no adequate means to enforce its will on offenders.
Although ultimately a failure, the League did have some impact on international relations after WWI. Probably the biggest asset of the League was a general feeling of optimism, which led people to believe that all wars could be prevented. The present-day UN operates under no such idealistic illusions.