Sailors of any type in the 17th and 18th centuries will still be following fashion. There are a few changes that are more specific to the seafaring trade, however. If you look at art depicting sailors of that time, you'll see they usually wear short jackets rather than the long coats with wide skirts, for obvious practical reasons. Slops, a loose over-breeches style, were also popular since they protected the clothing. Trousers were well noted in the mid-18th century as being popularized by sailors as they made their way into the dress of land workers and eventually the gentry. The phrases "sailors trousers" or "sailors jacket" were specific enough to be used as descriptors in runaway ads.

The most accurate search results are going to be from researching sailors or privateers rather than pirates. In simple terms, the easiest way to know if it's inaccurate is if it looks impractical. A perfect example are the tall leather boots pop culture loves to put on dashing men. Until you reach the very late 18th century this style was only meant for riding and fitted as such. The leather was not meant to bend and give easily enough for day to day walking, but rather stiff enough to support the rider when posting. Modern riding boots are still much the same. Sailors of all types would have worn leather shoes or pumps (heavy or light soled), most often tied rather than buckled since they're dealing with salt water. The shoes would have rotted through quickly, but it's a better option than going barefoot.