"Be still before the LORD and wait patiently for him; do not fret when men succeed in their ways, when they carry out their wicked schemes".
You know that you have truly surrendered to God when you rely on God to work things out instead of trying to manipulate others or to force your own agenda in order to control the situation. You let go and let God work and instead of trying harder, you find yourself trusting more.
Surrendering your life means that you will follow God's lead when you are not even sure where He may be sending you. You will wait for His timing, not knowing when it will come. You expect a miracle not knowing how God will provide and you totally trust His purpose without understanding the circumstances.
Christ showed the ultimate example of self-surrender the night before His crucifixion when He surrendered Himself to His Father's plan. True surrender says that if the circumstance or hurt you find yourself in is needed to fulfill God's purpose and to glorify Him, then you will take whatever may come your way.
This kind of faith and maturity does not come easily but true surrender is hard work and requires intense warfare against our self-centered nature.
Trust in the LORD with all your heart
and lean not on your own understanding;
in all your ways acknowledge him,
and he will make your paths straight.