What are the techniques in improving personality development?

Consideration of others is the first step and the biggest step in improving your own personality. When you are thinking about others needs and not about your own, good personality traits will be developed along the way and if you are being sincere with others, those good traits will be the ones that suit you. If you try to fake personality traits, others will be able to see through the sham; that's not an improvement at all. It will take practice to get there, but it will be worth the effort.