Be aware of your mental state. Failing to do so can cause anguish. Failing to do will make you a victim. Failing to do so can lead you to a life you did not choose.
When you are about to act on something, be aware the state of your mind. Do you really need that dress or is the feel good factor you really desire? When you about to give someone an advice-like what I am doing here- is it because you really care or are you just feeding your ego?
Be aware of the state of mind you are in and you save yourself from many pitfalls. Are you angry at the moment? Then, do not decide on anything now. The same applies when you are euphoric.
And don't react without being aware what is going through your mind. Yes, you need to decide fast but that is what you do. You decide.
Have a good day.