It's important to try accessories on before purchasing. They will wear differently with each head/body combination.
To test accessories -
Put on an accessory that wears in the correct slot and get the image url of the item you'd like to try on.
(Click on the item, choose Test Colors & Graphics, copy the Graphic Image at the bottom that ends with .img)
Then click on the accessory that you are wearing, choose Test Colors & Graphics again and paste the other item's
image into the Graphic Image box, hit test & do not close the test window!
Up top under your help menu choose about vzones, click ok. You can then walk around the locale, turn and see all views, etc as long as you leave the test window open and do not leave the locale.
If the item does not display correctly at all (as in far off up and to the side of your avatar ) try another accessory.
It could have incorrect settings for the item you are trying on.