As suggested by my CFI, You can always prep a plan for your NAV , sit in your armchair with a watch and all your gear and fly the nav in your head, fillowing the map, doing your clearoff checks following 10 minute/10 mile makers etc. Throw in some diversions etc. Helps to get the process burned into your brain a bit and will help you when you start doing the actual navs. Or...
Instead of the armchair, I fired up Flight Sim X, which had all the OZx scenery loaded for my local area, input the weather and flew that Nav on the sim, much more fun, and surprisingly accurate too. I think if you can get familiar with the basic process it will save you some time instead of learning it for the first time on the actual nav flight...