Trust the Lord with all your heart and lean not on your own understanding. In all your ways acknowledge him and he will make straight your paths. (Proverbs 3:5)
Making good decisions starts with a willingness to lay down your desires to God's perfect will and humbly follow his direction. The problem is that most of us don't know how to figure out exactly what God's will is in every decision we face, especially the big, life-changing type of decisions. 
So what is the correct way to make to make Biblical based decisions?  Well, the first step should be obvious, but we still can find ourselves neglecting the most important key- which is prayer.  We must always begin with prayer!  It is very important to enter prayer with a heart that is ready to obey and trust His direction.  We don’t want to pray just to let God know what our personal plans are.  If you are going to ask for His wisdom then you need to trust His ways will be right even if it means not getting what you pray for.  Remember He has your best interest in mind and He always knows the final outcome of any decision you will make. Be ready to accept God’s answer.  I'm not so sure that God will reveal His plan if He knows already that you won't obey. Submission is hard but there is always a reward with obedience. Decision making often requires us to use our faith muscles quite a bit.  It could be a process, and it takes time; so don't be in a hurry for a concrete answer.  Be patient and don’t move until you have complete peace about the direction.  Also make sure to evaluate and gather information that can help bring clarity for you. Most importantly be sure to search what the Bible has to say about your particular situation. If you have a difficult decision to make it is always wise to seek Godly counsel.   Proverbs 15:22 says, "plans fail for lack of counsel but with many advisers they succeed."   Don’t hesitate to ask for some guidance from a mature believer.  Make sure you choose someone who will lovingly tell you the truth, and not just tell you what you want to hear. Lastly it might be a good idea to make a list of priorities that God would have for you.  Ask yourself if this decision will bring you closer to Him, if it will bring glory to Him, and how it will impact or affect the people in your life.
By this time you should have quite enough information to make that final decision. Be honest with yourself and take the direction that the Lord leads you in.  There will be times when there is no right or wrong answer and you can make your decision based on personal preference.   If you have come to your decision with the sincere intention of pleasing the heart of God, and incorporating Biblical principles and wise counsel, you can then move forward with confidence knowing that God will work out his purposes through your decision. Romans 8:28 says that we know He works all things together for the good of those who love him, who have been called according to his purpose.  Trust Him and trust his process.  He will not lead you in the wrong direction.

**For similar post on making some challenging decisions, read Navigate Uncertainty