If, when you've printed at correct scale on the page, you still see drift - be sure to calibrate.
But I must share one more thing that really frustrated me when I started - my first printer didn't print true - over the page it stretched the output. It took me quite a while to figure this out. I printed a ruler and compared it to a true ruler, and found that I was getting significant stretch.
The only thing for that is a different printer (cutter calibration can compensate for some of it, but not perfectly.) Or - if you have this problem and it is only slight, learn to live with a few white edges (again, by compensating with manual edging in black/grey at construction time.)
Many of the models at http://oldschooldm.com have a tiny manually-inked edge hiding somewhere, and most people think they look awesome.
But - a good printer (true, and prints to edge) to go with your cutter - saves a lot of detail work.
