Draw at first one half of onions left, then the second — right, thus leaving a place between them.
We draw a bottom and top of onions.
We draw the directing. We paint over a bottom and feathers at onions, on we start shading with dark tone the right part of onions, gradually to the middle doing tone is lighter. We paint over the lower part.
For giving of contrast dark color is even more strongly strengthened, doing transitions, thus leaving not touched a place where a patch of light.
Watch still drawing of a cucumber, strawberry, a sunflower, a tulip.