I believe the key to great travel photography is 30% camera, 30% skill, 20% patience, and 10% creativity. Patience is really critical and it can mean waiting for the right time of day to capture a picture, or even just literally waiting until people move out of the shot. The latter is something that I am constantly bumping up against, and I am known to wait over an hour for people just to move out of a shot.
At the Mykonos windmills, it is pretty crowded, but crowds generally arrive at a pretty chaotic distribution. I will find a good place to take a picture as I have above, and if after 10 minutes it looks like I may get a big enough opening, then I will wait until I can get a shot with no people in it. Here I have before and after, probably about 45 minutes of cursing to myself. In the end, I get a shot mid day of abandoned windmills - in actuality, there are probably 100+ people in the area.