Critical thinking involves taking information and trying to apply it to answer some question or questions. It involves looking at that information in a very disciplined, honest, and careful way. A person who thinks critically does not make assumptions and does not allow their personal feelings and prejudices to determine what sorts of conclusions they will draw from the information they are thinking about. This sort of thinking can be of enormous value in everyday life.
Let's say, for example, that you are trying to decide whether to buy a particular piece of clothing. Let's say that you really want it and you think it looks really nice and, besides, it has the logo of some really popular clothing line on it. If you think critically, you will not let your emotions and your desire to have it control you. Instead, you will look at it more objectively. You will ask whether this piece of clothing is really that much better than one with no logo on it. You will ask whether you already have enough clothes and whether you really need this one. You will ask whether it is worth the amount of money you would need to spend on it.
In this way, critical thinking can help you. You may still decide to buy the piece of clothing, but at least you will be buying it for good reasons. Thinking critically in cases like this will prevent you from making silly decisions based on emotions or desires. This is why critical thinking can be useful in your everyday life.