What I believe you wanted to know was the best fields to earn good, and shouldn't be MBBS or BE.

So looking at insights of decision making about future, is definitely a big thing, and making choices can definitely be very difficult task to perform.

I'll help you out with the method I followed while making a choice about my career...

And making the best choice is definitely very crucial as all you future decisions are also relied on this one decision.

I made a list of

1. My strength
2. My weaknesses
3. My interests
4. My goals as a person

After which I had an insight so as to which 2 choices could work out best for me in the future.. you could also end up with more than one choice.

Next I made a flowchart comparing the 2 streams, with points like:

1. Wealth
2. Self time
3. Job opportunities
4. Family time
5. Interest
6. Acceptance in society

And viola! I had my perfect choice towards what was my best choice for a career which was becoming a doctor in the future.