Write as much as you can and keep writing. You’ll get better. In his interview on the BBC’s Desert Island Discs, Ed Sheeran was talking about songs, but the advice applies to any kind of writing.
Too many people think they’re not writers. When faced with a report or an important letter to produce, they worry that they won’t convey the right message or make a good impression. They believe that writing is a talent, something you either can or can’t do.
On the contrary, writing is a craft that you can learn. It may come more easily to some than to others but, as with most crafts, the more you practise the better you’ll be.
If you think I could help you improve your writing, do contact me.