You may have heard this a million times “Think Positive”. It works.
Smile. And smile some more. It adds to your face value and to your personality as well.
Read a few articles in the newspaper loudly. This will help in communicating fluently.
Prepare a chart that mentions your strengths and weaknesses. Now concentrate on the latter and find ways to improve upon the same. Do not forget to strengthen your strengths.
Practice meditation and yoga. It will help you develop inner peace and harmony that will reflect outside.
Do not live a monotonous life. Be creative and do something new all the time. Nothing bigger than the joy of creative satisfaction.