If you're feeling particularly creative, then you might want to go with an artistic outlook on tailoring. After all, seeing as in World of Warcraft we see lots of beautiful armor all over the place, you've got to wonder exactly who designed it. If it's made of cloth, then clearly someone must have woven it and stitched it right? Clothes don't make themselves, after all. Tailors do. And a tailor is just what you are.
It's one thing to play up your character as this brilliant fashion designer, but it's another thing altogether to actually whip out the clothes your character has made and prove it. The most obvious thing to do is just to say something like, "Look at this Black Mageweave outfit I made for myself! Isn't it cute? Tee hee!" But this rarely works well, as often the most beautiful piece of clothing your character has learned is something you've already seen other people making and wearing lots of times, long before your character came around. If you are diligent, though, you might be able to find rarer combinations of items other people skipped over which still look very nice when you put them together in your own way. Of course, you always have the option of sneaking in various Bind-on-Equip items you discovered in the wild (our bought at the auction) and claiming that you actually designed them yourself, too. As far as the game fiction is concerned, there's no reason this can't be true, especially if the specific combination of clothes is the fruit of your own creativity. To a lesser extent, you can also take credit for designing some of the less common cloth armor from high-level dungeons, although this way is fraught with peril, in more ways than one.
Back in the day, most high-level armor used to just turn up in the smoking remains of various evil entities, leading some roleplayers to wonder how these evil doers came to be carrying such glorious threads. To a certain extent, we still have this problem (and we continue to ignore it for the most part), but now that much of the best-looking armor is actually rewarded within the main city by turning in a token dropped by the dead raid bosses to a special exotic equipment vendor, it makes more sense that a normal person might have actually designed some of the armor -- or if not a "normal" person, then someone not hell-bent on destroying the universe, for once. Who knows, that someone could have been you!
Now, of course it is rather pretentious to say, "Ulduar Priest armor? Yeah... That was all me," but there's definitely some room for some of your character's creative expression: perhaps that pattern of light on the shoulders was your idea, or maybe you sketched out an initial proposal for the warlocks' mask thing, only yours had a hole for the eyes, so that the poor demon summoners would be able to see. Don't take credit for the whole thing, but don't hesitate to lay claim to one or two minor details and insist the whole design was a collaborative effort. Also don't hesitate to point out that if they'd followed your advice then we wouldn't be seeing so many blind warlocks bumping into things all the time.
In the end, remember, you are an artist! Fashion is every bit as much of a passion for your character as spellweaving (or whatever your character does in the way of killing monsters). Add details to particular items whenever you make them for people, describing the perfect stitching around the seams, or the awesome patterns on your very own brand-name Glacial Bag (much better than Haris Pilton's "Gigantique" bag, of course!). And in addition to making gorgeous clothes, remember to dress up as fashionably as you can, and share your opinions on fashion in general.
... Or don't. Certainly not all tailors are fashion designers who have to go out of their way to come up with unique and attractive designs to call their own. Your character could simply specialize in old standbys like the White Woolen Dress, or even the Tuxedo, and just hang out in your city's local tailoring shop, offering to sell or repair various items to anyone who walks in.
But what is a level 80 master mage such as yourself doing in the clothing store, you ask? Maybe the store belongs to a friend or family member, and you help out behind the counter whenever you're not saving the world from dire evil. Maybe you're vastly powerful but also vastly impoverished from all the potions and alchemical elixirs you have to buy, and so you're just trying to do something you're good at in order to get by.
Maybe knitting is just your hobby, something you don't even try to market in any way. It could be like your very own form of Zen meditation, to help you calm down from a stressful trip through zombie-infested necropoles.
Finally, tailoring could be a kind of philosophy, and an extension of your character's magic abilities, especially if you were to couple it with enchanting as your secondary profession. As Rylka mentioned in a comment on last week's article, it makes a lot of sense for spellcasting characters to see themselves as a "weavers" of things, starting with understanding how physical cloth can be woven or unraveled, later learning how to enchant or disenchant magical items with threads of magical energy, and finally mastering how to weave (or unravel) the raw threads of the world's magical energy, or even life itself. (In this vein, your character's flying carpet mount could be a sign of achievement in weaving magic and physical cloth together, rather than just a cool toy to impress your friends.)
Take tailoring as a kind of metaphor for your character's relationship to magic, and let it showcase how you see everything in the world in terms of threads and patterns, raveling and unraveling in accordance with the will of those who wield power over it. Your character may seek to become a god of the world through ultimate mastery of the essential threads of existence, or may submit humbly to a Greater Power and see his or her own soul as one of many threads woven by the hand of the ultimate Master Weaver into the great pattern of history.