Are you behind a router? if you are then you have to forward ports on your router to your computer to get top torrent download speeds (there are loads of faqs about it on the net).
Which torrent client are you using. From memory you can't go wront with the big 3... bit commet, azureus or utorrent (although the u is actually one of those greek symboly things).
Check the amount of people seeding the torrent of the thing you are trying to download. If it's zero then you aren't gonna have a lot of luck. If only 1 or 2 people are seeding then it may mean slow download speeds. This can make rare stiff a bit of a pain with bittorrent.
http://www.mininova.org and
http://www.torrentspy.com are both pretty good sites for torrents.
Not got much experience with limewire or ares. Did use emule a while back which used to be ok for rarer stuff.
For general p2p stuff then
http://www.zeropaid.com/ used to have a fair bit of info, ain't been there for a while though.
Oh and don't turn off uploading with torrents. Your speeds will go to shit if you do.
