Video coming in 2019
Many writers find that reflecting on issues that they have noticed (or that readers have pointed out) in their own writing can help them learn to avoid errors or revise their work more effectively in the future.
Is omitting necessary words one of your personal top twenty issues? If so, you may want to keep an inventory of the words you tend to omit. Will better proofreading of your work help you avoid such errors? Are any omitted words the result of unfamiliarity with idioms? Determine how you can reduce the likelihood of making the same mistakes again.