Most client writing problems I encounter are actually thinking problems. The biggest problem is they haven’t taken the time to identify a point of view, i.e., decide what they really think about a topic so they can communicate that clearly to the reader.
Instead, they “kitchen sink” it and assume the reader will sort it out. Here’s the reality: Every sliver of “friction” the reader encounters, meaning, every bit of work they have to do to get through your piece is an off ramp. And if their experience is bad enough—you may not get them back.
A way to remedy this is to put yourself in the shoes of the reader and ask the following three questions. What is it? Why should I care? What do you want me to do/think/see/say/feel as a result?
Another option is to hire an editor who will work with you to either remove that friction or help you identify where you need to apply a little more gray matter so the piece you’re working on will matter.