The phrase "best accessory" means a small item or detail that enhances or completes someone's appearance or outfit, making them look even better. Full definition
That being said, there's a whole lot of fun to be had by getting the absolute best accessory for the job. (jelly.deals)
While it's equally important to be armed with good accessories, like an exciting and edgy studded, mesh belt, keep your look to 1 - 2 main accessories maximum. (thefashionablybroke.com)
I adore that she recognizes a woman's best accessory in the end is her smile. (thevintagecontessa.net)