Let's say you have some files you've created and would like to share with the world, here's some do's and dont's that will assure it will be better preserved and won't become inaccessible over time.

• Put them somewhere where they can be downloaded over plain HTTP or HTTPS
• If you have the technical knowledge and want to host the files yourself setup an HTTP server or use some content management system.
• Host it in multiple places if possible.
• If it's a big file and you know how to do it consider creating a torrent file. The Internet Archive can do this for you (see next point)
• Learn about the Internet Archive. In fact, if you plan on licensing it openly upload it there.
• Consider adding it into the Musical Artifacts. You're reading the projects's wiki after all.

Avoid these, but sharing the file even under these circumstances is better than nothing.

• Require user logins or registrations to download the file
• Use File Lockers like Mega, Mediafire, uploaded.to, Baidu, etc. Why? These kinds of files end up deleted after some time, and generally are not served over plain HTTP, e.g., they require redirects and wait times.
• Put the files somewhere where they can't be crawled by search engines or indexed by the Internet Archive, e.g., file lockers, Dropbox, Google Drive...
• Upload anything non-free materials and mark with free licenses, as it's mistaken as parasitizing copyrighted stuff
• Ignore license field, causes license misleading (Default is CC-BY 3.0)
• Select a wrong license if your artifact is not original