Depending on the client you are using (Azureus, Utorrent, Bitcomet) there are certain guides to optimize speed. (Google the client and optimization) Changing the stock port in Any Bittorrent client is recommended, certain ISP's block those generic ports as they know what programs use them. Also don't expect good DL'ing speed from torrents with unhealthy trackers, I.E ones with low seeders, high peers/leechers. Last piece of advice, keep the firewall out of the way. Enable port forwarding for the respective ports, etc.