The first thing I did was to come up with a sigil that binds the golem.  Any method of producing a sigil will work and I've found it doesn't matter in this case if the sigil suggests the entity to the conscious mind.

The next step is to create some sort of physical object with which to contain the golem when it is not out doing work.  This object will also serve as the physical receptacle of libations.  You can get as creative or as simple as you'd like.  I just cut a small disc of wood about the thickness of my pentacle.  Eventually I'd like to try creating clay depictions of the golem but results have been more than adequate with the wooden disc.  I then carved the sigil onto the disc, painted it and generally made it look spiffy.

The next step is to decide what you want the golem to "look" like, even though the creature will only exist on the astral.  I just sketched out something pretty simple to facilitate visualization during what I term the "incubation" period. You should also decide on a name for it.

Next come up with some sort of ceremony for creating the thing within the disc or depiction of it.  Any methods of producing gnosis can be used and once gnosis achieved, the being should be visualized inside the disc as intensely as possible.  I suggest opening with the Qabalistic Cross or Star Sapphire ritual beforehand to emphasize the fact that we are microcosms of God (however you want to define him) and have the power to create life.

No apologies to Freud, the best way to "birth" the thing is by using unculminated orgasm to bring about a change in consciousness and then to allow release and smear the disc or depiction with the sexual fluids produced.

Visualize as intensely as possible the being within the disc at the moment of orgasm. You may also want to pour on it libations of milk, honey and/or blood.  How you get the blood is purely up to you.  I used my own for the first ceremony.  Then I used blood from drippy pieces of meat.  I also had some very open-minded female friends who allowed me to use their menstrual blood.

Repeat this procedure daily for however long you deem fit.  Until you can feel that the being is becoming more and more real on the astral level.  I call the initial feeding and preparation the incubation period.  Incubating it gives you more of a window and doesn't leave a lot of pressure to do everything exactly right on the first try.  You will begin to feel what works best and what doesn't and I advise you to omit or amend my suggestions in any way to find a method that works better for you.

*IMPORTANT*  If you banish before any sort of magickal work, make sure to remove the disc or depiction from the room before banishing during the incubation period.  You will banish the embryonic and germinating golem.  After sending it out on a task, however, I've found that using a banishing ceremony can act as a fulcrum to propel it ougive it a little push in case it wants to hang about.

After the incubation period, you can send the golem out to do a task for you.  Something of this sort should be said at the period of evocation and you may want to point a ritual dagger or wand at the disc or depiction for emphasis:

"Hear me now_____________!  I who fashioned you from the ether and shadowy astral substance charge you to rise from the disc bearing your essence and appellation.  I who fashioned you on the subtler planes for the sole purpose of working my will upon this one, command you now to hear and fulfill this task.  I who feed and feul your very existence evoke and entice you to________________.  Fulfilling this and all tasks I give you is your birth-right and justification for having been created.  Obey now with full cooperation and faithfully serve your lord/lady who created you and will destroy you if you are disobedient."