Did you re-open your port (port forwarded) on your router?
Besides that, I usually run the Setup Guide wizard (Options > Setup Guide) to the nearest server and use the recommended settings.
You could also go to Options > Preferences > Advanced > Disk Cache and use the following settings:
Members here will also advise you to go to your Preferences > BitTorrent and uncheck all DHT options, Local Peer Discovery, and Local Peer Exchange. If you use your client on public trackers, then don't disable anything.