There are many incredible temples, islands, and ruins to see on a trip to Greece.Roberto Moiola / Sysaworld/Getty ImagesI'm from Athens, and I've seen plenty of tourists make mistakes while traveling to Greece.Expand your visit beyond popular islands and attractions, but don't cram too much in one trip.It's worth it to do some research on smaller islands and local cuisine before your trip.Thanks to its ancient ruins, picturesque beaches, and inc…