Thanks for the suggestings.
To put it simply, this is following the good old "fake it till you make it" attitude, right? (Chakral affirmations and visualizations are tools, that I have yet to get into a bit more.)
But what I'm concerned with; is it even worth to pursure a change of personality, just for the sake of getting 4 other letters, the next time, I take the assessment? Because non of the personality types are inherently superior or inferior. Wouldn't it be wiser to shape my personality with my goals and purpose in mind an then use the test, to see where I'm at?
Alternatively, one could look for the mbti of some role model one wants to mimik and than try to shape one's persoality towards that indicator. But I think, that the other way is the more direct one.