Look, when I moved to Spain, 2 years after starting proper classes, people sometimes asked me if I was a native speaker.
For me, this was the ultimate compliment.
But, I also tried to learn French and I failed.. I took French lessons for 5 years at school and hardly learned anything.
You see, aside from my 8 years of teaching experience, I have:
First-hand experience of what it takes to become totally fluent.
First-hand experience of how you can study really hard and make no significant progress.
When I became fluent in Spanish, I did 3 things differently: