Torrenting is all about popularity, the more popular the thing your downloading, the likely it'll download at an alright speed. There are however a few things you can do to make sure that everything is running smoothly,
1) Open the needed ports in your router (check your uTorrent settings for the correct ports).
2) Configure the maximum number of connections you can have on a torrent, this determines the amount of people you can connect to, more doesn't always mean better though, somewhere between 50 - 100 seems to be the sweet spot for most.
3) Always keep your upload 7 kb/s or above, uTorrent limits it otherwise, some sites work out your upload and treats you in kind.
4) Join a private site, people often have more incentive to seed well on a private site, less hit and runners.