You're asking a really huge question, and at best you can only hope to get some pieces of inspiration from these posts; so don't expect any answers!
First of all, I think your mindset is detrimental. When you write things like, "my fingers cannot be articulate enough," "the more I practice the less I achieve," "I can't put the whole song together..." etc. you reveal a harmful self-deprecation that will only impede your ability to improve. What I mean to say is, smile!
Also, don't expect things to go your way in a matter of minutes, or even a couple of practice sessions. As Vladimir de Pachmann said, "If only I could tell you how many hours, years, went into those thirds!" referring to Chopin's nocturne, op.37 no.2 in G major.
Now for some practical advice. Every time you make a stumble, you have to turn that mistake into a principle. If you stumble in a trill, you have to say, "My trills need work." If you stumble in a scale, you have to say, "My scales need work." If you stumble in a complicated contrapuntal passage, you have to say, "I need to work out counterpoint better." Every mistake relates to a principle.
Then, everytime you approach a piece, you see the same things pop up over and over again: trills; scales; counterpoint; arpeggios; fast chords; parallel chords; everything that gives you a problem in place, will do it in the other, if it goes unchecked. That's why every time you stumble, you have to search for the correction.
When you find the correction - and sometimes you will, sometimes you won't - you have to then do two things: 1, try and apply it to other pieces with similar problems, and 2, remember the mindset that led you to the correction; forget saying things like, "I can't," or "my fingers can't;" instead, say "I have solved this problem, and I can do it again."
Any problem at the piano exists at so many levels of difficulty, and if you can solve it at one level, it doesn't mean it will be easy at the next, but it means you have a record of success that you can apply to the next case; you have a permanent head start in solving those problems.
If you are zealous about correcting every single error, every time, you will see very quickly an amazing improvement in your piano playing. Your thinking will go from small errors to big pictures, you will be able to sustain a piece all the way through, and your experience of success will aid you in learning all new pieces - as long as you don't let yourself forget it.
Walter Ramsey