I believe change is really simple at its root. but everything associated with change is what seems hard to surpass in order to make that change part of the new you.
Old habits die hard? it seems the reason for that is because of the foundation those habits rest on is firmly established in oneself.
The people I know exist in thought. If I think of my friend X, I can identify and know him without having to actually see him. X is selfish, X likes to embarrass others he is with, X drinks too much.
Now what I know of X comes from accumulated knowledge of how he acts around me since I've known him, and what others have said about him.
If I meet X tomorrow and he does not act like my stored memories of X, I may start to think something is wrong or different about him. (maybe this is where my thinking of this topic goes astray, maybe most people don't think this). If X started not being selfish like he has always been, and started involving others in decisons. I may thing X is up to something, I might think he is just being nice to get something at a later time. I'm just using this as an example of what ones image of another is.
Now, as far as changing myself. I think its as simple as making the choice to change. If I want to start expressing my feelings more, or want to show more enthusiasm in others conversations, I can start doing that and eventually my skills in the unused personality skills will develop.
But, my issue that I fear may keep me from doing what I want is: how will the people I know react to this? and if someone was to question me about it, my thought now would be that I may subconsciously think "I must be wrong" and then revert to my old ways.
how do you overcome that fear others may react adversely to your change and stick with it?