Send authenticated mails. Send an email or two to your own Hotmail/Gmail address each day (or at least regularly), and make sure to interact with the email (read/reply/forward/put in folder/etc.). Personally, I use Hotmail for reading my shopping lists.
If you end up in your own spam folder, "Not junk" is your friend. If you don't get through at all, do the escalation dance with Microsoft until the situation improves.
Once you reliably hit your own Hotmail inbox, start sending mails to A FEW others as well. Verify that they receive the mail, and ask them to add you to their trusted sender lists, press not junk, etc, and keep bugging Microsoft if they just discard your emails silently. Once you have a few people doing that, reputation should improve quickly.
