The usual is a common reply to what will you order? or what are you up to?. It is often abbreviated, in Canada, to the first syllable of usual, as in the youzhe. How would you spell this abbreviation? Is there evidence of a standard or more common spelling?
Any way you want to.
It's gonna be slang in any case, and that gets spelled in lots of ways. If it becomes as common as gonna, it'll develop a normal "eye dialect" spelling.
You could argue for at least the following possible spellings, as communicating the syllable /yuʒ/: youzhe, youzh, yuzh, uzh, uzhe. They all have their problems, and only the ones that work will stick. So try'em all out. This is the way the language grows.
I would argue against all John Lawler's suggestions. There is a pretty good argument for technical use of 'zh' by analogy to the relationship between s and z (i.e. s:z :: sh:zh where z and zh are voiced versions of s and sh, if I have the terminology right). But I think Lawler is coloured by his profession as a linguist. I don't think there is any standard English word spelled with 'zh' (is there?), so it would confuse many non-linguists. Add to that that all the options given look nothing like 'usual' and that it is clear that context isn't going to help people unfamiliar with the term. I think 'use' would be an obvious choice except for the collision with the common word 'use'. All that said, I don't have a better suggestion. ('uge' like 'luge', jokingly?)
"usge" - this is the most common I've seen and has the benefit of looking like "usual".
See the entry for "usge" on UrbanDictionary. "Yooj" has also been used.
There is an informal English word ending in "zh" that is in current use.
"zhuzh", pronounced "ʒʊʒ", and defined as "To make something more interesting or attractive", e.g. The stylist said he would zhuzh up the outfit with some jewellery.
Hence, I would suggest the spelling "yuzh", or "yoozh".
I find most of the usual (hah) spellings difficult to understand at first, because they don't look like the original word much at all. I suggest "uszh", or something of the sort, as it catches the eye with the shared first two letters before going on to specify pronunciation. It's still up in the air as I see it though.