I try to be thoughtful in my approach. By this I mean that I consider the nature of the communication, the urgency, the audience and the value. I will spend more time on something that has more value. I will tailor my approach based on the audience, urgency and nature of the communication.
I volunteer for work that involves writing (documentation, emailing someone outside our team, communicating with stakeholders, etc).
I get someone I trust to review my writing if it is more substantial than a simple email, or any communication that will potentially be read by a customer/client/stakeholder or similar.
If I don't have someone to review, I use a fairly common "write-review-edit" approach - where I write, then put it aside. I return to review, make notes, set it aside. I then come back to edit after another break. I repeat this until I'm satisfied.
I've taken courses and workshops on writing that contributed to what I have learned as well. These were all taken many, many years ago but I have retained valuable lessons from them.