How do I find Preferences in bittorrent or utorrent on a Mac?
Welcome to the world of the Mac!

Unlike many other operating systems, most Mac OS X apps don't have a menu bar in the app itself but use the system-wide Menu Bar.

When uTorrent app is in focus (click on it once if you're not sure), the Menu Bar will show the menu options for uTorrent. 

One of the options will be "Preferences..." as you can see in the screenshot below: