The easiest way to get upload on trackers is to upload your own content, on Red that's not very complicated if you have access to a library or another more obscure source of CDs that might not exist on the site yet.

The other way that requires more storage and longer term commitment is just to seed everything you download forever, including things that you grab on freeleech events or with tokens (A "bonus" given out on Red that you can redeem for a free download).