The T-1000 was no different in T-2 than it was in T-1, besides the obvious 180 degree mission change.
In T-1, it leant how to track Sarah, wear clothes that would make it blend in more, and various other things to make it a more efficient killing machine. In T-2, its mission was to protect John physically and mentally. by doing what John asked it, and learning from John's reactions and views on life, the machine was able to 'seem' more lifelike, thus again blending into society and creating a more comforting atmosphere for those that he was trying to protect.