Increasing the Torrent speed fully depends on how much Seed And Peer your torrent file have.If your torrent file which have very low seed and peer than its very hard to get a good downloading speed.So its good to have more Seed And Peer.
Now,if your torrent have a zero seeds than your downloading will never get complete.
Than what to Do??

Because of SOPA we have lost some good services like Torrific.com .I have got this site which leeches torrents on server just like Torrific.com , you can download torrents Directly from download managers, like IDM.

about torrific.com but torrific is down and now you can migrate to this site