I start my day with listening to audio books, you can choose what you like to hear most because it's different from one to another, some people like drama other adventures, i watch English videos with subtitles, sometimes I turn off that option to test my abilities in listening.
Sometimes I read fifteen words per day and read a topic which contains theses words in text.
I think you should work on three sides listening, practicing, writing.
I'm still working on improving my level and i didn't achieve my goal yet, but that my way in learning, I will put some links here, I hope it will help you.
By the way studying grammar is something essential for being better.
I taked courses in business but it will help only if you are planning to work in business field.
Www.cambridge dictionary. Com