The first thing you have to do is to ‘learn how to learn’, that is, memorising a list of words or follow complex grammar rules is definitely not the road to fluency.
1*Switch from passive to active learning.
Would you learn how to cook by reading a recipe book? Probably not. You would most likely learn by cooking, and by burning a few dishes, using too much salt, and messing up. It’s the same with Business English - we need to step into the kitchen and get a little burnt sometimes. By this I mean, practice whenever you have the chance, don’t be scared of making mistakes, and don’t worry too much about getting it perfect the first time. We learn much more from from doing than from reading and listening.
2*Use it or lose it.
Get rid of all the things you learnt that aren’t helping, and make a list with the specific things you actually need (phone conversations, writing emails, negotiating, giving presentations, understanding a conference, asking a girl out, you name it). Once you have your goals, your direction, then you can collect the most common phrases that native speakers use in those situations.
3*Join a class.
There are countless options out there, but there is no faster and more effective way than having a teacher to help you out with the specific points you need to improve.
Active learning: start using the language as much as possible, remember only the most useful things you need.
By joining a Business English class,you will learn faster how to communicate effectively.