Nothing here yet.
A good Christmas shirt or jumper has a bit of weight to it before you have even got it on the hanger properly. You pick it up and the knit sits dense in your hands rather than floppy, the print on a shirt feels printed with intent rather than sprayed on in a hurry, and the collar on anything with buttons has a bit of structure that tells you it will still look like a collar by three in the afternoon. Cheap festive gear tends to announce itself the second you touch it, thin and slightly crunchy, like it was made for one photo and nothing after.
Colour is where most of this falls apart, so it is worth being fussy. A deep green, a proper burgundy, or a navy with a subtle pattern will see you through every gathering from the office do to Boxing Day without looking like a costume, and they all sit nicely against darker trousers and a plain jumper or coat. Bright red works on fewer people than the shops want you to believe, and loud novelty prints, the ones with reindeer doing something they should not be doing, are fine for one afternoon and genuinely hard to wear twice without someone commenting. Avoid stacking pattern on pattern, a busy shirt under a cable knit covered in snowflakes is a lot, and metallic thread or sequins look expensive in low pub light and slightly sad under office strip lighting. Before buying, check the weight of the knit against the light, have a proper feel of the seams round the underarm since that is where cheap stitching gives up first, and check buttons are stitched through rather than glued, because glued buttons last about as long as the enthusiasm for the party itself. Sizing runs oddly generous in a lot of novelty knitwear, so try it with a shirt underneath rather than trusting the label.
The clash to watch for is doing too much at once, a loud shirt with a loud jumper over the top, or tartan trousers under a patterned top, turns a decent outfit into a fancy dress costume by accident. Keep one loud piece and let everything else calm down around it.
A good one gets better with age in an odd way. The colour mellows slightly after a few washes, the knit relaxes and moulds to you rather than sitting stiff, and it starts to feel like a jumper you own rather than one you borrowed for the occasion, which is exactly how it should feel by the third Christmas.
Nothing here yet.