Trademark Specimen Guide - Class 25
Examples of generally acceptable specimens for clothing and apparel include sales hangtags, collar tags and website screen shots showing an online shopping cart option,
Examples of unacceptable clothing specimens include pictures of the logo on the front of a t-shirt, baseball cap, sweatshirt, etc. These examples will likely be considered as "merely ornamental" by the Trademark Office Examining Attorney and thus be refused as a valid specimen. The following are examples of specimens that would likely be refused by the USPTO Examining Attorney.
Of course, at the end of the day it is up to the USPTO examining attorney to decide what is and what is not acceptable. However, providing a specimen that is more likely to be considered acceptable from the beginning can greatly reduce the time and cost it takes to get your trademark registered.