Surrender means to give in and according to the Islamic psychology; it means to give up on worldly desires that are surely the means of disruption and an obstacle between the happiness, satisfaction and tranquility.
Without manifesting oneself or soul, no one can find the real happiness. The real happiness lies in self-expression. Ability to express yourself is only possible when you are well tuned with your inner self. And this is the purpose and teaching of Islam.
In fact, in every religion they teach the same thing. Buddhists find their inner peace by reaching an exalted state of Nirvana whereas; followers of some other religions find their ultimate peace in meditation or salvation. Muslim saints and sufis proclaimed that the real satisfaction lies in having no desires. Desires are all those materialistic dreams that a person runs after all his life. Neither they get fulfilled nor the person gets his inner peace and remains disturbed, in melancholy and grief.
Surrender to Allah Subhana wa Tallah is inevitable and once the person gives up on his or her materialistic desires he finds freedom from his worries and thoughts. Surrender to Allah Subhana wa Tallah means to announce your defeat and denounce the ugly will. The same will that is against the will of Allah Subhana wa Tallah. The best way to surrender is to fix your gaze and heart upon remembrance of Allah Subhana wa Tallah. When you find difficulty in life or have pain remember and ask only Allah Subhana wa Tallah. When you are happy and life is smooth then say Alhamdolilha and remember Him the most. Surrender your rebellion soul and keep it busy in the same way the Holy Quran says to get inner peace and betterment in both of the worlds, here and hereafter.
“Surely in the Remembrance of the Divine do the Hearts find Satisfaction” (Qur`an)