One easy and quick way to speed up your BitTorrent downloads is to adjust the number of maximum half-open TCP connections that are allowed. The default is 10, and this is far too low. You actually want this value to be in the range of 50 - 100.

If you are using uTorrent, you can go to Options -> Preferences -> Advanced options and you'll see an entry labeled "net.max_halfopen". Adjust this number up to at least 50.

If are using BitComet, go to Options -> Preferences -> Connection and you'll see an entry labeled "Max half-open TCP connections". Adjust this number up to at least 50.

If you are using Windows XP SP2, this change will not actually work since the OS limits the number of connections. If you are stuck in this manner, there is still hope for you. You can download a pathc here (http://torrentfreak.com/evid4226patch223d-enzip/) that will allow you adjust the maximum allowed at the system level. Once you apply the patch, you can then make the change in your uTorrent or BitComet BitTorrent client.