Unlike most of the scribes work, the get can be written with any material that is lasting, ink, paint, blacking, lead etc. (Gittin 19a) and written on almost anything at all, an olive leaf or even the horn of an ox - both of which sound very difficult to achieve - though not anything living or which could be called food. Even earthenware pots and leaves inside the pots are considered as possible writing surfaces!
R. Judah b. Bathyra felt that it should not be written on a used sheet with erased writing on diftera (unprepared) parchment as the text could be altered without it being noticeable. However the sages said it was valid.
It can be written in any language.
From the talmud there is the general comment that 'if a man wrote a get for his wife', suggesting that the norm was to do it yourself, but even then reference is made to payment to the scribe for the service and how the scribe should be instructed. Pretty much any Jew is qualified to write even, states the halacha, a deaf-mute, a child or a lunatic. A woman may even write her own get!
However as would be expected the norm is for it to be done by a skilled scribe in kasher ink in Hebrew as with all the other works, though it is normally written on paper (I use parchment paper).
The word get does not actually appear in scripture at all but is a Talmudic name. Interestingly enough the Vilna Gaon notes that the letters gimel and tet do not appear next to eachother throughout scripture either within a word or even the first and last letters of adjacent words, they are always separated. This alludes to the separation between husband and wife and hence the title get is very appropriate. Tosafot to Gittin 2a explain that the numerical value (gematria) of the word is 3+9=12 and that is why a get is written on 12 lines.
The real rules center around the need for it to be written for a specific woman with special intention that this be the case. It must be word perfect, and like the k’tubah it must be signed by two witnesses. The get is written with a slightly different approach. The spaces between the lines are further apart but to ensure that no one should insert extra words between the lines, the ascenders of the lameds are lengthened and the nun becomes a very long letter with a descender.
To ensure that it is correct Maimonides includes the full text of the get in his Mishneh Torah.