I agree with Tempest on the Nav prep, nothing worse than reading a question wrong. I took the test and though I spent a half day before studying, I didn't think it was too bad. Use a nice mechanical pencil, a .7mm worked best for me as it has a stronger "lead" than a .5mm. Also, get a white Hi-Polymer eraser, Pentel makes them, instead of a Pink Pearl as these are a lot easier on paper and not as abrasive as the Pink Pearl. I used to be a draftsman in a previous career before CAD and those are what we used. Mike Pyzel's book is what we used last December and is a great book to learn from. Good luck!