one of the common concerns most Christians have is how to find out their purpose and God given assignments.
Here are 8 steps you need to follow
Decide in your heart and determine that you want to be useful in Gods house.Every thing you do with God must start from the heart. Once you have a Godly desire in your heart, the enablement of the spirit will be made available to you.
2 Corinthians 9:7-8 NKJV
 So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver.  And God is able to make all grace abound toward you, that you, always having all sufficiency in all things, may have an abundance for every good work.
2. look out for any area that will advance the kingdom of God where you can use your skills or talent in. As long as you notice a need in the kingdom of God, fill it. The principle here is to start from the known to the unknown . Meaning that even if you do not know the specific area God has called you in, start from the one you do know.
Ecclesiastes 9:10 NKJV
 Whatever your hand finds to do, do it with your might; for there is no work or device or knowledge or wisdom in the grave where you are going.
James 4:17 NKJV
 Therefore, to him who knows to do good and does not do it, to him it is sin.
3. Be faithful and consistent in that assignment that you are doing. Give your best. Do not make any excuses. Serve God more diligently than you will serve ceaser. God deserves the highest quality of service, plus he pays far more than any human organization can ever reward you with. Faithfulness is what determines if God will open up the next level of assignment which you have been desiring to you.
Luke 16:10 NKJV
 He who is faithful in what is least is faithful also in much; and he who is unjust in what is least is unjust also in much.
4. If you have been faithful, God will move you to the next assignment or next level of responsibility, or to your core assignment. God will find a way to orchestrate this to happen. Don’t worry about how it will happen. Just focus on being very faithful.
5. As you continue to serve, you grow more in grace and knowledge. Grace increases with use. The more you deploy yourself to the assignment, more grace is released so you can do more.
Matthew 25:21 NKJV
 His lord said to him, 'Well done, good and faithful servant; you were faithful over a few things, I will make you ruler over many things. Enter into the joy of your lord.'
6. You will be rewarded in time and eternity. God is a rewarder. He never forgets anything done for the sake of his people or his kingdom.
Hebrews 6:10 NKJV
 For God is not unjust to forget your work and labor of love which you have shown toward His name, in that you have ministered to the saints, and do minister.
Revelation 22:12 NKJV
 "And behold, I am coming quickly, and My reward is with Me, to give to every one according to his work.