Like the other guys say, let it bend more along the mid limb and tips.
A lot of people leave the tips stiff and some designs demand it (Holmgaard style), but if you allow every bit of the limb to bend you can get a much longer draw without an expolosion!
Here's an example of a more semicircular shape.
Note the chalk lines drawn on the wall around the limbs, they help you see that each part of the limb is bending more as you move out along the limb.
You can see the left limb (lower limb) which is shorter is having to bend much more than the top one. Without the whole limb bending it wouldn't come back that far. It is a nice quick bow (Hazel)
Del