Deep Trance
The level of trance you achieve depends greatly on your relaxation, concentration skills and will power. To enter a deeper trance, i.e., Theta level and beyond, you have to concentrate much more and for much longer, on the mental falling sensation aided by breath awareness. The first level of trance, i.e., when you get very heavy, is quite deep enough for projection. I strongly advise against forcing yourself deeper than a light trance, until you have plenty of experience with the trance state.
How can you tell if you are entering a deep trance? There are four very noticeable symptoms:
An uncomfortable feeling of cold that doesn't make you shiver, coupled with a steady loss of body heat.
Mentally, you will feel very odd and everything will feel extremely slooooow. Your thought processes will slow down as if you had been given a strong pain killing injection.
You will feel disassociated from your body, i.e., a strong floating sensation and everything will seem far away.
Total physical Paralysis.
Note: These four things, ALL TOGETHER, signify you are entering a deep trance.
Do not mistake the mild floating sensation you sometimes get with light trance, i.e., as you astral body comes loose. Or the slight loss of body heat from sitting still for a long time and the mild paralysis, i.e., the heaviness, for a deep trance. The sensation of deep trance is quite uncomfortable and unmistakable for what it is.