The successes of WTO and failures you can get it from many references and books who write about advantages and disadvantages,as comparative studies.

http://www.nber.org/papers/w9273

Can read the paper in the above link

Once i worked on this topic.

Article The Role of Charismatic World Trade Organization and the exp...

Hope this helps

One of the successes is a legal framework for world trade which must be followed by 164 member states (membership growing).

On the negative side the failure of the Doha Round since 2001....

On the positive side the successful negotiation of the Trade Facilitation Agreement (TFA).