ACGG Charter Member Chuck Grace shares his checkering techniques in this 2 part tutorial. He's been checkering for 49 years now and has tons of tips to share.
Part 1: https://youtu.be/_YN0ZnHd5_0
You can find printable checkering stencil paper here:
https://github.com/ZebGunmaking/tools/blob/main/Stencils/Checkering/README.md