While it is notoriously hard to figure out what to cover and what to omit, there is a handful of purely linguistic tricks. toby544 provided a good example of those, and there are plenty more to be found (another set of key words you might find useful: informative writing).
I will focus on something else instead. The mindset.
The mind in turmoil struggles to communicate thoughts clearly. I find confidence and clarity absolutely essential for writing. There is no need to omit the thought process entirely while sticking to the subject matter like you suggest in the comments.
Text becomes hard to read because of not-so-necessary fluff: overuse of passive voice, waltzing around conclusions with "probably" and "might indicate", dealing almost exclusively in hypotheticals. These are also the hallmarks of a large part of academic writing: dropping careful formulations is also no good, after all. So how to find that balance, then?
By grouping all the "maybe, maybe not" and "this is not conclusive" bits together. Do not let your - and your reader's - mind wander around too much during a single explanation. You might stop at some key concepts and briefly address possible concerns if it doesn't require going too much in-depth. If it does, find a simpler explanation.
Finally, it is impossible to cover everything required to understand the subject in a single body of text. Spend a lot of time considering the scope: who is your audience? What do and don't they know?
This is a lot of work, and the answers can't be given in general. Some examples of questions can.