I started by gently removing the bark and most of the cambium with my drawknife. I know some people like to leave the bark on until later in the process but I just don't like drawing out the bow on the dark, scaly bark so I take it off right away. I'm careful not to damage the first layer of sapwood so if I need to leave patches of cambium in places that's ok at this point. I'm extra careful around bumps and knots so I don't violate the back of the bow. I leave little islands of bark around the knots that I will clean up later with different tools.
Next I take out my card scraper and start removing more of the cambium still being careful of the first layer of wood.
There are still some spots where there are dips and valleys that the flat scraper can't get into. for those I use my curved scrapers to gently remove the stubborn cambium.
I clean up the knots a little but don't bother with them too much. I'm just trying to get off the bulk of the cambium so I have a decent surface to layout the bow. Once I rough out the bow I'll clean up the back more thoroughly. No reason to do detail work on wood I'm just going to chop off with a hatchet! This is what it looks like when I'm done.