Caveat: I'm not doing this entirely by hand, but since my dovetailing is largely manual, I figured it's fair.
I'm making a small walnut cabinet and started dovetailing the carcass today.
I finally started using the 'blue painters tape' trick to mark my pins. On this dark wood, I can finally see the layout lines. The FWW article that suggested this only put tape on the top of the pin board. I found it useful to use 2" wide tape and tape all 3 sides. True to the article, it gave me more confidence to saw up to the line. Having the tape on the sides makes cutting straight so much easier for me.
Last, I'm not sure why I haven't seen something like this before. When cutting, paring, marking, measuring dovetails, I have 3-10 tools on the bench at any time, half of which want to roll off the edge as soon as I turn my back. A notched 2x4 makes a nice tool till (holds 'em 'TIL you get around to hanging them properly.)
I know, I don't cope very close to the line. That's because I clean up the bottoms with a pin router.