2 Answers

Just as it is very difficult—if not impossible—to improve your vision through exercises, it is also difficult to improve your 6th sense capabilities beyond what you were born with. On the other hand, you can improve your sensitivity to your 6th sense, just like you can be more aware of your other senses.

One thing to remember is that the 6th sense seems to work less the harder a person tries to use it. It seems to work the best when you don't try.

Consider the exercise above, where you recalled times when it seemed you were experiencing your 6th sense. Now think back and try to remember exactly how you felt when that event happened. Then try some predictions, guesses or other exercises similar to those explained in Sixth Sense Experiments.

By practicing using those feelings, you may be able to improve your 6th sense capabilities. Note that getting those feelings also includes being more sensitive to all of your senses. 

Source: http://www.school-for-champions.com/senses/6thcheck.htm#.UuymsvldXHQ

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