A lot of attention to getting the beta reader and what you want. One panelist had two perfect ones, one who would give a gut reaction to things, and one who would analyze structure and info-dumps and the like. And listening to the editor, who is not there to oppose you but to make the story better, to point out the info-dumps, and that it's not clear in the first fifty pages who's going to be the main character. It is perfectly ordinary for these people to come up with crucial and enormous flaws in your work, which will change the whole thing. Yes, this can be painful, and hard to wrestle with, so it helps to sneak up to it and absorb it bit by painful bit and let it perculate a bit and come up with new things. Walks are helpful. Also showers.
Things to look for before you get to the readers. Repeating your words. Repeating your sentence structure. Repeating the same subjects half a dozen times -- especially when it's "He" (or, I presume, "She").
Then there is letting it go. Sometimes the editor is needed to say it's good enough and yank it away from you. You could always make it better, especially as you grow as a writer. You would write a different book five years later -- but you should be working on your new books for then, then.