As was posted in the comment section, there are guides to writing good essays. Most advice you will read IME can be summarised as: keep trying to say it. i.e. don't expect the reader to get it without a concerted effort to structure, write and summarise it as clearly as possible.
What is more puzzling (for me) is how to know what you should say.
One example from my study: I was writing an essay on a poet, who treats the landscape as something that depends on her; toward the end of the essay I noted that she doesn't imagine the landscape is created by her.
This caused the reader great confusion, when I could simply said e.g.:
- I have explained how the landscapes she describes "depend" on her (highlighting a possible contradiction), but nevertheless, the landscape isn't something she "creates" (explicitly saying it isn't a contradiction). The world she writes about would have existed without her, but not in the manner it does (trying to elaborate to show how the contradiction is only an apparent one).
This is a subset of the need to adopt the reader's perspective. From the linked to guide:
Adopt the reader’s perspective. One of the most valuable techniques
for improving a rough draft is to get out of your own head and read
the essay as someone else would see it. Imagine a reader who is
intelligent and sympathetic, but also thoughtful and constructively
critical. Will this idealized reader understand what you are saying
and find it plausible? It often helps to imagine a specific individual
as your idealized reader. Whether you use a friend or even your
instructor as an imagined reader, you may be surprised how many
helpful suggestions he or she has to improve your essay. Another trick
to adopt the reader’s perspective is to read your essay out loud. You
will often hear things that you have trouble seeing. The basic point
of this technique is that we should, in the words of best-selling
author Kurt Vonnegut, “pity the readers,” because “they have to
identify thousands of little marks on paper, and identify them
immediately.” 2 This is hard work, and we have to make it as easy for
them as possible
So, making the right things explicit is important. Aside from making sure the reader doesn't think something self contradictory, what other things must be made explicit?