There are many ways we can change our negative thoughts and become more and more realistic. We should Focus on all on all those areas which generate positive energy. We must remind ourself that positive approach towards one and all can change your self-esteem.
We must read about the positive thinking strategies that would help us the most. We must catalogue them and remind ourself to pause and change our way of thinking each time we are being critical of ourself. As we become more comfortable with each new way of thinking (for example, learning not to apologize or accept blame for other's anger) try adding a new positive thought strategy to our list.
Sure shot way to become more and more positive in letter and spirit.