Personal change can go in any number of directions, from improvement to degradation to a mix. There are however workable technologies for positive personal change. If the interest is to become, say, more compassionate, or more tolerant, or more organized, or more responsible, the best direction is to observe people who have these qualities, see how they do it, and apply it to oneself. If observation does not suffice and an explanation is necessary, such can be gained best, not from someone who's had the desired qualities all their lives or to whom such come naturally, but rather from someone who did not have them initially and developed them later. The reason for this is that such a person would be more conscious of how he did it and will be able to provide more intelligent explanations, whereas someone to whom the trait comes naturally may not be conscious of how it can be achieved.
Along the way are some people whom one should studiously avoid. A person who simply does not like you will not suggest positive paths of improvement; he will respond with abuse and destructive rather than constructive criticism that will attack the good in you as much as it will attack the bad. Also to be avoided are those in ministry who see the entire human nature as evil and for whom nothing suffices except complete personal evisceration.
To be avoided as well are many people involved in personality psychology. According to these, a "sociopath" cannot by definition be a good person, however hard he works, however much good he does, and whatever work he does on himself. The practical meaning of this is that such people have nothing of merit to offer the people they see as being sociopaths and will spend their time and energy not helping such people but rather shackling their minds and destroying them from within. Another example of this is the approach toward the no-longer-existent "narcissistic personality disorder" and its tireless champion Sam Vaknin. According to Mr. Vaknin, once a narcissist always a narcissist. This is glaring illogic. If people are responsible for who they are then they can get rid of any trait that they deem undesirable; and if they cannot do that, as his theory implies, then people are not responsible for who they are and cannot be judged for the outcome. We see practicioners of this brand of psychology practicing glaring illogic - illogic that is entirely unsuited for people engaged in scientific inquiry.
A friend of mine used to tell beggars who asked her for change that change comes from within. I have a vision of a beggar coughing up quarters. In most cases change involves both internal and external components. It is necessary to sincerely want to accomplish the change; and it is useful to look to people who have the desired qualities - either to observe or to ask for explanation. And it is also necessary to know whom and what to avoid.