The generalized process:
Stay relaxed, and keep your mind focused.
Once you feel that little tug behind your eyes, remain relaxed, focused, and still. That's the trick to the simple way of projecting, and it takes time. For some it's very difficult to do, so I suggest meditating first or running around or anything that will help you calm down and relax.
You do not have to see your astral body actually separate. The process itself is simple. When you astral project, your astral body, along with the lesser subtle bodies go with it. This separates the various forms of projection. Try working your way up the ladder. Try mental projection sometime if you haven't already, get used to that, then try astral projection. It will be so much easier.
First your bodies bodies begin to level off on different planes, causing for some, a vibrating sensation. There are 2 planes directly on top and below this plane, the physical plane. They are not spaced out like most other planes, in fact something can exist on either at the same time. So your astral body, when first projecting but not completely lifting off just yet, remains in the planes either directly above or below this one. This gives the notion of not separating yet, but really your bodies are already almost there. All you must do from here is to create a connection, which typically comes naturally but some people have to do it consciously, and climb. Climbing is the actual case of projecting further into the astral planes, this may take some practice when projecting consciously.
Everyone astral projects, but not everyone is aware of it. It really is a naturally occurring habit that one can with practice learn to do voluntarily.
To help with climbing I suggest trying dream control, it works wonders for you when you start projecting.
Versus Etheric Projection:
Astral and Etheric
Then differences can occasionally be difficult to spot.
Mainly for those with more psychic ability.
Strange to say, but yes, it does get more difficult to tell the difference if one has more psychic ability.
It's rather easy to imagine.
For one, think about what they are.
Astral Projection is the temporary release of the soul, of which is attached to the physical body.
Etheric Projection is the release of the soul, of which is not still attached and takes over the vital signs of the physical body leaving the physical body clinically dead.
EP is often confused with the Near Death Experience (NDE).
Psychics and regular people alike may see either, and either can not be differentiated except the capacity the subtle body has to effect the physical plane.
Meaning, the subtle bodies of astral projection and etheric projection are exactly the same except one (etheric body) is much more dense therefore more so capable of effecting the physical plane of existence.
Therefore, say in the case of a medium, they will be able to see and sense the astral body nearly as well as the etheric when a regular person with no such experience will most likely only be able to see or sense the etheric body.
For those more experience with the paranormal:
* The etheric body can be compared more to the density and capacity of a poltergeist
While as...
* The astral body can be compared more to the density and capacity of a specter