If you visit Athens in summer, don't spend more than 1 or 2 nights in the center of Athens and spend a night on the beach: Hotel Electra is in the Plaka neighborhood in downtown. From there you can walk to the Acropolis in only 10 minutes. It's important to get up early and see the Acropolis in the early hours of the morning when there isn't a line or a lot of people. A good time to go is 7:30 / 8:00 in the morning, but not much later. Once you've seen the Acropolis, take the little tourist train that is on the street. You can catch it right there at the exit of the Acropolis and it takes you back 1 hour through the city.