The success of our life is greatly dependent on how well we understand what great acaryas in our sampradaya want from us. Success in the life of a devotee means how he is capable of pleasing his guru and the whole guru-parampara, and in this way he will be able to please Krisna. It can be done by meditating on the desire of a pure devotee and Krisna will give us all the facilities to accomplish it.
Bhaktisiddhanta Sarasvati Thakur reformed gaudia vaisnavism in a very significant and radical way. He felt a very important need to change the traditional gaudia vaisnavism because it lost its power of connecting ordinary people with God. He fought against hereditary brahmans, stating that spiritual qualification should be proved. He also wanted to re-establish varnasrama. And third, he said that vaidhi sadhana bhakti and raganuga bhakti are the stages of one path.
The desire of Bhaktisiddhanta Sarasvati Thakur was to preach everywhere and to anyone, so that people would be connected with Caitanya Mahaprabhu and His mission. He invested the same desire to the heart of Srila Prabhupada, and Srila Prabhupada in his turn also invested this desire in the hearts of his followers, who are trying to invest this desire within our hearts. If we fulfill this desire, by spreading the mission of Sri Caitanya Mahaprabhu, our life will be successful.