You are talking about the unread appearance of your writing; about whether your writing appeals to its readers before its first word has even been read.
Good! Visual appeal is part of marketing and marketing is crucial for building a following.
But why are you asking for writing techniques to handle a marketing issue? Writing is about content and pace and style. It's about what goes into the page, not what the page looks like. Get the content right first and then come back and make it pretty.
You can't do it the other way around. If you make it pretty and then fix the contents, the addition or removal of words may mess up your pretty. If you are trying to handle both content and pretty at the same time, then you are not investing enough attention on your content. Outline your story, then find the right words for each scene and then, if you aren't already being dragged away by the idea for your next story... go back and make it pretty.
So what techniques make the text pretty? I only know one. Add carriage returns! Breaking text walls into short and varied paragraphs softens long dissertations.
Don't worry about grammar, or about the laws defining how many thoughts should go into each paragraph. Nobody remembers those rules any more. The only survivor from the age of grammatically correct writing is that we still hit the carriage return each time the speaker changes in a dialogue.
Other than that, you can pretty much do what you want.
...Just like I have while writing this very pretty, un-wall-like answer. Seven paragraphs of varying length, short ones up front, 3-5 lines each after the hook has been set, and short near the end to keep them reading.
Was it easy to read?
Was it appealing to look at?
Would you have read it if it was still a Text Wall?