As you have probably figured out by now, Prezi is a completely new way of presenting and is unlike the linear (slide by slide) approach we've all grown used to over the last 100 years or so. Because Prezi is so different both technically and aesthetically, we need to make sure we approach it in a very different way to how we might go about designing a PowerPoint presentation.
It goes without saying that a presentation designed in any media should have a good degree of planning first, but even more so in Prezi. The reason is that Prezi's infinite canvas gives you such a huge expanse of space that it is very easy to lose elements of your design within it.
By simply planning your Prezi in the right way, you can save lots of time in the design stage and really take advantage of this space.