Electrical problem with Ford Focus.

We've had this car for about 3 weeks and 4 times when trying to start the car
we put the key in the ignition and nothing happens, pop the hood and give the
positive cable a giggle and about 5 seconds later there is some clicking sounds
from the passenger side of the engine, go back into the car, insert key and
everything works as it should! Any and all help is appreciated.