Expose yourself to a situation where there is no escape, i.e. the only way out is to embrace the cognitive function you are not used to, but are longing for. Combine that with a shift of your mental state where you actually enjoy using that cognitive function. And let loose of every way of thinking you have identified with and considered to be "you".
It is a shock therapy, it's a bit radical, and it is scary, but it works. When you do this, you will encounter a mental border; something that tells you that beyond that is a way of "seeing" that is not you. If you approach this border slowly or by simply "simulating" the new cognitive function, you will not change fundamentally. You will be continuously running up against a hill and never get to the other side. You will have to make a leap of faith "into" the new cognitive function in order to change considerably.
I did this with Ne, Fe, Fi and Se, with various degrees of success. It's not like you change totally, but you change in large shifts. It's a good way to become more balanced, in my experience.