Game plan is very important in gambling. If you come to gambling with a hope to win big but have no plan, consider if you lose in the beginning it will just broke your heart and maybe you will never return to gambling. With experience, you will get to know how to come out from losing situations.
That's the first important thing you have to learn.
Without game plan you will be loss and you will not know when to stop when winning or when losing.
It's important to have a solid and working game plan but you need to be discipline to be able to initiate your game plan effectively.