The simplest way of increasing the speed of torrents only and only while you might be using public trackers is to add as many trackers as possible which will help you in getting seeders from all of these sites and hence increase the speed of your download the logic is as below
Tracker 1 had 5 seeders + Tracker 2 has 6 seeders + Tracker 3 has 8 seeders + and so on , so you will get the cumulative bandwidth from all these seeders.
You just need to right click on the torrent select properties and then edit click on the edit tracker button or add tracker button and you will have the option to add