You need to know the laws of your country and how the State is wasting money.
For example politicians may start pumping money into renewable energy, so it may be wise to invest in that sector because it's basically free money. You need to learn how to access to those free money threw by politicians for the current cause.
You also need to have a good accountant and also try to stay up-to-date as much as possible when it comes to your country's laws on investments, pensions, etc This is important not only because you want to respect the law, but because you want to break it or game it without getting caught.
All those books about getting rich, like Napoleon Hills, etc are most of the time scams or motivational books. There are some insights, in some books, sometimes, but sadly due to how the market for these books is, good insights are surrounded by a lot of bullshit.
In the end what works is selling something, getting paid and knowing the laws.