How do you know God's will for your life?
First, you must give your heart to God. This is where it belongs in the first place. You belong to Him by original Creation, and then, by your own free-will, learning and knowing that He is your Creator and that you belong to Him, you must re-join yourself to Him by giving your heart to Him. This is done by the aid of the Spirit of God, commonly called the Holy Spirit. Christians use Jesus as the One you confess your sins to in order to have them forgiven. This is right.
Second, once you have given your life to God through Christ, with the aid of the Holy Spirit, you will be guided by your heavenly Father (God, often called "The Lord" in the Old Testament) to what you need to do. By a variety of ways the Holy Spirit will guide you.
It often takes these elements and the following sequence.
First, He will impress on your mind something.
Second, He will give you an actual experience in which to practice what He has impressed you to do. This can be described as the School of Christ. Some refer to it as the School of Hard Knocks. God will not give you anything that it is impossible for you to pass through, but will with the situation, give you all the support you need to pass through the experience He is giving to you. Another way to describe this is: This is a healing process you are going through to regain what God designed you to be in the first place - in your relationship with Him, and also in your relationship with others - your family, friends, those you work with, and any others you come in contact with during your daily activities.