You don’t have a mitre saw featuring a laser beam? No problem, me neither. However with this tip you will achieve results with the same accuracy. It only takes few seconds more. Layout your workpiece with an unknown angle and drop it on the miter saw bed.
First, lift the saw guard and insert a small scrap about 2″ long in the sliding slot between the front end and the stop (you may need to adjust its length according to your miter saw). This will keep the guard up for the setup.
Second, secure a 3″ X 6″ temporary guide, made out of a thin scrap, to the saw blade with a spring clamp.
Third, remove the small 2″ scrap to free the blade guard (if not the saw will freeze) and let it sit gently on the workpiece, as shown.
Finally, keep the saw down with your right hand so the temporary guide will meet your workpiece while your left hand will align the guide (and the saw blade) with your layout line.
This is laser accurary without the laser itself. Just a little left- and right- hand coordination.