It really is a broad question and depends on what you are wanting to achieve in life. However it must also be pointed out that you can have intelligent change by not changing for other people as well. If you are coming from the most authentic part of you and heeding the lessons of life you can change in massive ways and not have that change be the result of what others want for you.
As far as the personality part of your question. To me personality is not at our essence but a construct of our own human mind. Living authentically requires deep self evaluation of all the aspects of our personality to discard anything inauthentic that doesn't serve our higher evolution.