Use the side entrance: Most people don’t know that there are actually two entry point to the Acropolis. The side entrance is located near the Acropolis museum and is significantly less crowded than the main one. This option’s route saves the top of the hill for the finale as opposed to the first stop.
Enter around 5pm: This is going to be the least crowded time with hopefully the best weather. Entry stops at 6pm so your climb up should not feel rushed. Though it’s later in the day, It will still be light out for pictures but not too hot for some uphill walking.
Buy tickets in advance: To avoid time waiting in line and to garuntee your ticket, buy it in advance online! There are many different options so make sure to read through them carefully. I will link the website here: https://www.acropolis-tickets.com/?gclid=CjwKCAjw04yjBhApEiwAJcvNoUYPTLI1T9uSCI8PbOUJ--GuUjrTBObJNINedFmzpdOTzDr-_CqUWBoCSLcQAvD_BwE
Purchase tickets that include the audioguide: One of my favorite parts of the experience was learning about the detailed history of the area and the intricacies of all the views the Acropolis has to offer! It also has a location feature that automatically matches you with the audio for your exact location.