Start the download, and check the speed under the "Down Speed" tab.
Right-click on the download name, and click "Properties
Under the "General" tab, locate the "Trackers" box. Scroll down to the end of the list, and press enter to make a new line. Copy and paste these trackers into the box. It's OK if you have duplicates - uTorrent will ignore those ones. Don't erase the existing trackers, either. The more trackers, the more chances to increase your speed.