Here are several possible answers:

You wake up and everything you do that day is effortless.
You wake up and everything you do is hard.
People in your life tell you that you are doing great.
People in your life tell you will never succeed.
Your bank account balance reaches $100,000 for the first time.
Your bank account balance is $-1.63 for the 8th time this month.
People around you love you and say great things about you.
People around you loathe you and want you dead.
Are you starting to notice a pattern here?

The problem is that at one time or another, I have experienced all of these and at each point in my life, I was still “on the right track”, I just didn’t know it at the time. The problem is that there is no way to know if you are on the right track, you just have to have faith. It is one of the reasons why “God” for me is a worthwhile construct. Regardless if you believe the myth of the old bearded white guy who lives in the clouds or not, the belief in God is about having “faith” and in order to be a success in life you have to have “faith” that you ARE on the right track. Even mistakes and setbacks don’t mean you are on the wrong track, they just help you better define for sure what the right track is so you can get back on it. See? That is how it works. Life is a “participation sport”. You have to be actively doing something in order to win at life. It honestly doesn’t matter what you do, just do… something… anything.