One thing that really helped me when doing navs was writing out all the radio calls days before actually doing the exercise. I would sit down with my maps and look at exactly where I was going,what airspace I would be flying through and then work out what radio calls I would be making and who I'd be making them to. It worked well.
Don't just have tracks/headings planned. That's bloody obvious. Look at your maps. Check what/who you'll be flying over and try to forsee any potential conflicts. Cockpit ergonomics play a huge part. Like Atlas said, don't have bits and pieces of paper floating about. Get comfortable and work out what works best for you. $100 knee pads won't do you many favours either. Good old clip board from the local newsagent does the trick. Write your radio frequencys on your maps. Nothing worse that mucking about with the ERSA looking for the page for whatever field you're flying into when you could have just scribbled all the info onto your VTC.