Most people spend two days in Petra, but If you’re going to see Petra in a day, you must start early. The park opens at 6:00 AM. Stop and explore the Treasury right away before the crowds arrive, and then make a beeline for the Monastery. This lets you see the two most popular (and photogenic) monuments without the crowds and avoids congestion on the Al-Deir Trail.
You will have hiked about 5 miles by the time you’ve come back down their Al-Deir Trail, so it’s the perfect time to stop for a snack and cup of tea at the restaurants at the base of the hill.
The time should be roughly 10:00 when you get up and move again, and before the full heat of the day, so it’s a good time to climb to the High Place of Sacrifice. It’s better to hike the Farsa Valley Loop clockwise, starting from the theatre, because it’s easier to climb stairs and walk down the trail. Plus, it lets you get the climb done earlier and explore the Farsa Valley tombs on the way down.
It will be lunchtime when you get down Farsa Valley from the High Place of Sacrifice. It will also be your third pass through Colonnaded Street and Street Facades, aka the main drag. By now, you should know which monuments interest you and where you’d want to eat lunch. This is the time to thoroughly explore the main drag and grab a bite to eat.
You have one more side trail to explore before leaving Petra – the Royal Tombs. It’s a relatively short hike up to the tombs, but if you’re feeling motivated and don’t mind the heat, you can continue on the Al-Khubtha Trail to the Treasury Overlook.
You’ll want to visit the Nabatean Theatre and Tomb of Anesho after the Royal Tombs and continue out the Siq to the Visitor Center. This one-day Petra itinerary had over 12 miles of hiking with 2500′ of gain. You can still return for the Petra at Night show later that day, but Aaron’s Tomb will have to wait. Depending on your schedule (and motivation), you can do activities around Petra, like the Turkish Baths and Little Petra, the following morning without re-entering the site and re-hiking the Siq.
You can turn this into a two-day itinerary by saving the Farsa Valley Loop and Palace Tombs for the second day. I’d save Aaron’s Tomb for my third day in Petra. Adding extra days also lets you explore things to do around Petra too.