I'm no tournament player, but generally 'seriously' learning/playing fighting games is like learning to draw. Learn and practice the fundamentals and they will take you where you want to go. Above all it will take time, so be patient and be willing to self critique and even invite others to critique your work. Hopefully there will be a replay function like in TTT2 for that. Don't be afraid to ask questions and don't be afraid to do some research and study what high-level players do with your character. There's a 'what character should I choose?' guide floating around somewhere for Tekken 7.
As for Tekken related stuff, other people in this thread can advise you much better than me.
But generally, learning fighting games is a life-long venture. There's no real stopping point other than simply stopping.
Thanks! That is a worrying analogy for me, my drawing endeavours have..... Not turned out well haha.