Below I shall demonstrate how I make dovetail markers
Woodraphic All New Dovetail Jig Marker Hand Magnetic Saw Guide Marking Hand Cut Wood Joints Gauge - Aluminium/Uhmwpe/Neodymium Magnet/Slicone Skin (1:6 for Soft Wood) - Amazon.com
Magnetic Dovetail Guide by Timmy2Hands | SimpleCove