In private trackers, it can be difficult to find enough leechers to upload more than you download. Most of yhe content will be sitting there with many people seeding compared to how many people are trying to download.

To balance the system, private trackers will give you points for the amount of time spent seeding. You use the points to purchase upload credit to keep your ratio up.

If you’re using public trackers (that you can access without an account) then this doesn’t apply. If you’re struggling to upload enough then it’s probably that you aren’t contactable. To transfer, one of the parties needs their port forwaded to create the connection. If you have yours forwarded you can share with anyone, if you don’t then you can only share with peers that have their port forwaded.