Another often forgotten aspect is taking up insurance poilicies which come in handy in emergencies.

I wish somebody told me about the importance of having a passive income.

I similarly wish I knew more about financial management: how to save for retirement, how to create a budget, how to interpret insurance plans, how to build a credit score, etc. Even coming from a developed country such as the US and attending a top business school, we received no financial planning training and thus learning how to set up bank accounts and investment plans was difficult.

I agree with the others below. I did save but I wished I was smarter with money and learned more about investing it properly. 

I wish somebody had told me how to grow my savings.

Save, save and save no matter how little. I saved a bit but i feel i could have done better.