Te is not about planing from within, its about being in a logical relationship with your environmental logical factors, so for example responding to a legal necessity or trading opportunity - so the so called plans of Te arise from the environment, from a meeting, etc and they are very dynamic.
Our initial difficulty with this is that we do not understand or respect the protocols that are involved and we hate their restrictions and fear their consequences. Better understanding of the outside world would be helpful. Its not exactly a psychological development. Its a learning from experience.
If you are INTP or INFP, what you are struggling with, in regards to having your own planning from within, is both the immaturity of tertiary Si and much more so the total absence of Ni.
Ni is defining yourself as someone who has a certain priority, a clearly defined way, something that you're all about, that you must accomplish, for at least a period of time, until its done, not just subjectively (what understanding you seek) but what you must mean to the world. Such dreams are usually deconstructed by our iconocastic Ne and for us, it requires complicated circumstantial incentives, that will convince us, that one possible manifestation of will stands out as being superior to others or as being absolutely required. Its like we only dare to become someone with a solid goal, when we are forced to.
Immaturity of Si is more uncomplicated. Si just grows organically. Initially we have unconscious routines that may be silly but we can get thinking involved to upgrade our habitual preferences, so they consist of powerful tools, such as good diet, sleeping routines, etc, so the same repetitiveness, that once made us seem lazy, makes us more efficient at ... staring at opportunities as they pass by. you could set up a script that watches youtube videos for you and posts a comment under each: cool lifestyle bro, but i'd rather watch another video before commuting.
If an I**P can be confused for being Te dominant, they are probably I*FP, because the rigid, bookish appeal to authority or authoritarianism of Te, the protocol fetish, the demand to force an involvement with everything upon everyone, concepts like duty and guilt and submission, these are the perfect antitesis to Ti but align well with Fi.