Don't think so hard. You are not the thoughts in your head. Your worries, anxieties, guilt, and other negative thoughts are not you, and getting lost in them poses a huge impediment to being in the moment. Stopping yourself from thinking so hard is an important step toward mindfulness. As you probably know, it's also very difficult to do. Here are some ways you can stop letting your thoughts rule your existence:

Stop thinking too much about the future. A certain amount of planning is good, but there are many, many things that are out of your control. You cannot control what will happen in 5 or 10 years. When it comes down to it, you don't even know what might happen tomorrow. Make a conscious decision to stop worrying so much. When you find yourself obsessing, do something to bring about greater mindfulness, like stepping outside and breathing fresh air for a few moments.

Accept pain. When life brings tragedy, being in the moment means experiencing pain instead of trying to ignore it or make it go away as fast as possible. Allowing yourself to feel negative emotions – fear, guilt, anxiety, sadness, and anger – is an important part of living in the present.

Try not to let your emotions get wrapped up in past occurrences or worries about the future.

Breathe. Taking several deep breaths can help you return to the present moment. During those times when your thoughts are jumping from problem to problem and you can't seem to focus on the present, stop and breathe. Take five deep breaths, inhaling deeply through your nose and exhaling through your mouth. Focus on your breath as it enters and leaves your body.

Source: wikiHow

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