Make sure that the steering wheel is solid and free from fractures or looseness at the hub.
Check that the column is solid. Turn the steering wheel
from left to right as you test for security. Check that
there is no play in the steering wheel. A slight amount
of play may be normal but
basically any turn of the steering wheel should translate immediatley
to a change of direction.
If there is a lot a movement in the steering wheel which fails
to alter the direction
of the car this would indicate either a loose nut at the hub of the
steering wheel or a worn steering rack or bushes. The steering should
feel secure and firm.
Power steering. The steering should become easier and lighter
when the engine is started. Failure would indicate low fluid in power
steering system or worn/faulty power steering pump.