I found a stick of good length, perhaps four and a half or five feet, which I knew to be dry. Then I proceeded to bend it a little and whittle down the areas that seemed most resistant to bending. When I had cut away the worst spots, I strung the bow with a double length of tough string (a single strand, which I tried first, snapped). I actually braided another bowstring for extra strength, intending the other to be temporary. (It took me half an hour to braid it). Anyway, when I'd strung the bow I proceeded to the process which I have seen referred to as tillerring. That is, I placed the bow upside-down on a piece of wood and had someone else pull the string to bend it,then continued to whittle it down. You can find pictures of the process online.
Everything went pretty smoothly at first, the bow gradually grew more supple, so I decided to fire a couple arrows. I was overeager. The first shot was fine, especially considering that I could thus far only bring my bow to half draw. But on the second shot I applied a little more pressure, and--you guessed it--I had the bow in pieces about my ears. Figuratively, that is--fortunately. It snapped very violently, and I was lucky indeed not to get hit.
What went wrong? Probably I was simply too hasty and not careful enough. But my choice of wood may have played a role. My stick was made of Magnolia wood--I had nothing else available. I've never heard of a bow made of magnolia wood, and perhaps now I know the reason.