This question has been raised before and you might like to search the forum.
I've heard Master Lin answer this question and his answer is like jeffdengr's. Your experience of the emptiness is at levels or depths or layers. It is not a you got it or you don't, is more or of a how much have you joined with the emptiness.
Master Lin's directions are all you need to go into the emptiness. Mentally focused, physically relaxed and still. Those three elements work together to help you go into the emptiness. You don't have to consciously try and go there, just know that you want to then mentally focuss on you qigong. The more you follow the six keys to success the deeper you will experience the emptiness.
You are perfection.
Iam2 
