Already wrote in some topic, I will share my experience here.
Learn to MANAGE your money. To do this, you need to realize 2 key mechanisms:
- accounting
- planning
Accounting is a somewhat formalized task where you record ALL of your income and expenses, preferably by "cost/item/income item", with time stamps
Planning is a solution based on expenses/income of previous periods, plus calendar planning of income/expenses, for the next period (month/quarter/semester/year/year/...).
This will allow you to optimize your expenses, to avoid the condition called "cash gap" (not sure if I'll get the name right in English, but I hope so

), which will eventually allow you to move to the stage of accumulation and/or investment of free funds. Or it will show that you should work harder and spend less, as your expenses regularly exceed your income.... But this is also a good indicator, at least you will understand WHY this is the case