If you search around the internet there are a couple ways to tie your obi. One method has your obi crossed in the back while the other does not. There are also a couple different ways I have seen the knot tied in front. Personally I prefer the method where the belt is not crossed in the back and the front knot resembles a fortune cookie if you look at it closely. For a tutorial on how I tie my obi please check out the following video.