Albert Einstein has an opinion: Take lessons from the past, live today, and wish for tomorrow.
I really agree with his idea because he just explained the mentality of having a clear mind. First of all, you mustn’t forget about your past actions and prevent yourself from making the same mistake again. Also, try to understand what you did wrong; do not just try to escape from doing the thing that you made the mistake in. But make sure you understand the wrong action you did, and try to draw a conclusion based on it.
For the second, live today. Because you might not have the same opportunities as today in the future. So know the value of living like this right now. For the last, wish for tomorrow. You can’t know what will happen next, right? So why don’t you just wish and work for your wish to come true? You can shape your future just by yourself, never forget that.