More generally, it could be useful to have writing tools which help you taboo specific words, to try and write/think more clearly.
To be clear, I don't (currently) think there's a set of words which just should be tabood generally, including forms of "to be" -- but tabooing specific words at times can be very useful.
Another example is the idea (which is related to nonviolent communication) that we shouldn't use "should" and related words (such as "ought"). Trying to speak without these words for a time can help eliminate specific mistakes in thinking.
Another tool for writing plainly is Hemingway Editor, which tells you when you use complex sentence structure, big words, extraneous words, or phrases with simpler alternatives. It also marks the reading grade level! Unfortunately, although it marks passive voice, it doesn't mark all occurrences of "to be", so it doesn't help practice E'.
The best thing (for me at least) would be a Chrome extension that makes it easy to taboo specific words whenever you want, anywhere you're writing on the internet.