Wikipedia:Drafts still have standards
 | This is an essay. It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints. |
 | This page in a nutshell: Just because a draft isn't yet an article, doesn't mean you aren't subject to Wikipedia's content, inclusion, and user conduct policies when editing one. |
Draft articles are not (yet) articles. They are not hosted in article space, they are not indexed by search engines, and they are not yet subject to Wikipedia's standards and policies, including being reliably sourced, adhering to a neutral point of view, complying with the guidelines set forth by the Manual of Style and so on.
However, much like the sandbox, just because they are subject to less standards, does not mean there are no standards.
While it is true that the rules about what is allowed in draftspace are relatively lenient in many regards, that does not mean that you can simply do whatever you want in draftspace because, "it's just a draft!" Drafts are still required to adhere to Wikipedia policies with legal implications, including but not limited to the policies on copyright and biographies of living persons. Drafts that constitute attack pages or copyright violations, or which violate other relevant policies, may be speedy deleted. And finally, if you tendentiously resubmit your draft to Articles for creation without addressing the issues raised by reviewers, you may face sanctions, and your draft may be deleted.
Additionally, Wikipedia's policies about civility and editor conduct still apply to drafts. While this may be of no concern if you are the sole editor of a draft, if there are any other users actively editing it, you are still required to collaborate and communicate with them as needed, and treat them respectfully. It is inappropriate to edit war in draftspace, just as it is in article space. Vandalizing drafts is still vandalism, and so on.
And finally, and especially if there are other active editors involved, Wikipedia's inclusion criteria and content policies, including but not limited to notability, verifiability, neutral point of view, and so on, are still relevant in draftspace.
These policies may not be urgently relevant, but they are still important, for one simple reason: you, and anyone else who may be working on the draft with you, ideally want the draft to become a proper article. As such, it is best to build your draft article with Wikipedia's policies in mind. If anything you add to a draft article violates these policies, it may be removed, and "it's just a draft!" is not an excuse for keeping the material.
In short: edit a draft article just as you would any other article. It's supposed to be one.