Life can be simplified into something like this: (1) Purpose, (2) Effects of different courses of action, (3) Decisions.
So firstly through God’s word [in secular terms, this simply means some source of moral inspiration, i.e. something that gives us an idea of what we consider to be meaningful or worth accomplishing] we continually grow in our understanding of what God wants for us and the people around us. This gives us our purpose (1).
Then, as we go about our lives, we try to understand the effects of our actions (2). Some parts of the bible help with this, especially Proverbs, though usually only in the form of general principles. So the specifics we gotta figure out ourselves.
Finally, we must make our decisions (3) by trying to see which courses of action (2) best fulfill our purpose (1).
(1) can be defined as something dependent on the free choice of every individual, i.e. ultimately one must personally appreciate what one deems to be a worthy goal to pursue in life. Also known as Morality.
(2) is generally under the purview of Science, which basically studies cause and effect.
(3) is generally encompassed under Economics, which studies how different methods can best fulfill certain goals.