In my view looking at various scriptures while quite helpful in determining a moral code is not the last word for the development of one. The main advantage of scripture study in this respect is that if one follows the strictures laid down one can avoid a lot of suffering. The other method for determining if there is moral law and how one should live in order to conform to it is to observe the beliefs and actions of oneself and others. In this one has to be as objective and honest as possible.
Just a few areas into which one could delve:
1. What does the practice of homosexuality bring about in the lives of those who practice it?
2. What does sexual promiscuity deliver to those who indulge in it?
3. What effect does dishonesty have on those who engage in deceit, lying, cheating, etc?
4. How does indulging in the use and abuse of alcohol and drugs effect the lives of those who engage in this?
5. Does crime pay? If so, how so?
There are many, many more areas of life one could engage. Also, one should not just confine observation to the person or persons who engage in various practices and beliefs but should also take a look at the effect these have on family, friends, businesses, communities and nations. One should also observe the consequences of truthfulness, chastity, humility, charity, forgiveness and the like. After all a moral code is more than just forbidding destructive belief and practice - it is also a statement of what is positive and constructive.
"After all a moral code is more than just forbidding destructive belief and practice - it is also a statement of what is positive and constructive."
I've always felt that these are the best arguements for morality. God's laws have a real and tangible use. Man's laws (not eating shellfish) are imperfect and sometimes useless and stupid.