[PTC CREO NEWBIE] How can I model a simple light bulb?

Hi there
I am in need of serious help in modelling/constructing a light bulb.
Could someone please help my by giving step by step instructions on how i would go about this? I know that we need to do a revolve and a helical sweeps but how would i go about going this.
I just need to do the outside, overall shape of it. So i don't need to make the inside of the bulb, eg filament etc.

here is a picture of the type of bulb i need help modelling
http://www.chineselight.com/uploads/130107/1_114009_1.jpg