How to decide What is Good (or Right)? Or can you?

I came across this chart I had made about 10 years ago while teaching students for the philosophy olympiad. This is a rather simplistic view of the idea of Good and my understanding has evolved a little after this. This doesn't directly address the question in the title. However, this chart tells the uninitiated, the following:

1. There is no ONE concept of Good or consequently, Evil. It is a matter of perspective.
2. There is therefore no easy way to claim that something is EVIL without hesitation. For instance, consumption of drugs or alcohol can be considered as Good according to Hedonism.

So, when a philosophy student wants to determine if X is good, (or write an essay) his program has to be as follows: 

1. Determine the root axioms of your philosophy, i.e. the fundamental principle upon which you will build your reasoning
2. Gather evidence in support as well as opposition of X being good
3. Apply your principle to X and construct an argument just like a mathematical proof
4. Finally and above all, keep in mind that another principle or philosophy can prove your conclusion wrong. That, there may be many principles which are equally useful at arriving at the truth and that they may give different answers.
5. HENCE, try to:
1. Counter all other principles which could be against your conclusion. i.e. try to show why they are not valid
2. If the above is not entirely possible, then try to create doubt regarding the other principles or philosophies, i.e. point our flaws in them
3. Finally, give a solid reasoning as to why your chosen principle or philosophy is the best applicable to determine if X is good
4. Hence give your conclusion

This applies equally so in personal life. If knowing the goodness of something is really important, one must follow these steps as critically as one can to arrive at the conclusion. You may ask, what if we apply the wrong principle or make some mistake in our reasoning. Yes, this is always possible. Even with great philosophers. Hence, they follow a method of dialog between them and other equally competent minds. You could discuss with other intelligent people yourselves. And if such is not possible, then you should rest your mind by realizing that this is the best thing you could do ... reason your way to the truth. Hence, if you are proven wrong you need not repent.

Hope some of you try this.