Kev it's really depend of your connection and your ISP.
Like said Jason some ISP will try to cap or block some port on your connection and they can limit your upload.
Also if you have a slow connection and a firewall without any configuration for your bittorent client that will have consequences too.
There is no way to cheat the serveur if some people upload huge amounts it's because they have a very good connection and their ISP doesn't limit them and their client/firewall is well configured.
I'm lucky for have a good connection and ISP and i did myself the firewall configuration and i'm using utorrent client and eveything is fine and last thing i keep my torrents open then my upload ratio become bigger.
I hope it helped you !