Simple trick on how to sew straight lines

This trick is great to use when you have a small allowance. For example, my sewing machine is designed for inches measurements, I need it in cm for this specific pattern and that was the best trick I used. For Sewing a straight line you can find many ideas. Another one I use is a metal magnet that helps also for sewing straight lines for top stitches. Hope this helps someone. Thank you for watching.