The Ask page has been changed; see also The new ask page is now live on the network. I am writing this meta question as discussion so that we can collect ideas about how we can make the best use of the new features on Chemistry. If we reach consensus on a proposal, we could write the corresponding feature-request later.
For example, the contents of the "Draft your question" sidebar on Chemistry are still limited to a short standard text:
On Physics, however, the sidebar has a longer custom text:
I guess a useful sidebar on Chemistry could look quite similar. In particular, it could include a link to our homework guidance. By the way, our homework guidance already has a (unfortunately well-hidden) similar attempt to guide new users through the (old) ask page:
We could also think about tag-related error warnings like this one: