Nothing can be achieved without practice.
The tai chi must become your own. Slowly over time you must polish it like a stone, nourish it, grow it, enjoy it, love the feeling of mental and physical peace and stillness that it leaves you with.
Ultimately it becomes your own personal journey, the Tai ji becomes a way to find the ever moving still state of your own personal Tao. It gives you a framework for living, being yourself and moving naturally and comfortably through your life.
I always advise students to practice one thing they learnt that night when they get in from class, just to own it. Sometimes even the next morning that piece of information has receded and is not so clear. If every week one new thing is assimilated, slowly over a year, over ten years progress is achieved.
So, practice. Everything can be achieved with practice, perseverance and patience. Try to let go of expectation and judgement and just enjoy the practice. It really is everything.