if you want beautiful water, good food, and somewhere quiet to actually relax, you are in the right place.
definitely ask whether your hotel or rental has parking. just like in a lot of places in greece, parking can be a pain.
navigation is fine around the main towns, but do not trust it blindly when heading to coves or mountain villages. you can end up on what feels like a goat trail pretty quickly. check the route before you leave. road lighting at night is also pretty bad in some areas.
if possible, avoid july and august. those are by far the busiest months.
it is an island, so prices are generally higher than on the mainland.
la scala is probably the most famous beach club on the island. i have been to thassos a few times but never went because it is not really my kind of place. it has more of a çeşme or bodrum style party atmosphere, which feels pretty different from the rest of the island.
and honestly, do not plan your whole trip around whatever youtubers say is popular.